Towards Ultrahigh Sensitivity and UV-Vis-NIR Broadband Response

Subscriber access provided by UNIV OF LOUISIANA

C: Plasmonics; Optical, Magnetic, and Hybrid Materials

Towards Ultrahigh Sensitivity and UV-Vis-NIR Broadband Response of Organolead Halide Perovskite/Tinphthalocyanine Heterostructured Photodetectors Fobao Huang, Yingquan Peng, and Guohan Liu J. Phys. Chem. C, Just Accepted Manuscript • DOI: 10.1021/acs.jpcc.9b00278 • Publication Date (Web): 10 Apr 2019 Downloaded from http://pubs.acs.org on April 10, 2019

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 22 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

The Journal of Physical Chemistry

Towards Ultrahigh Sensitivity and UV-Vis-NIR Broadband Response of Organolead

Halide

Perovskite/Tin-phthalocyanine

Heterostructured

Photodetectors Fobao Huang 1, Yingquan Peng 1, 2, Guohan Liu 1, 3*

1

Institute of Microelectronics, School of Physical Science and Technology, Lanzhou University, 222 South Tianshui Road, Lanzhou 730000, China

2

College of Optical and Electronic Technology, China Jiliang University, 258 Xueyuan Street, Hangzhou 310018, China

3

Institute of Sensor Technology, Gansu Academy of Sciences, 229 South Dingxi Road, Lanzhou 730000, China

*Corresponding

author. Institute of Microelectronics, School of Physical Science and

Technology, Lanzhou University, 222 South Tianshui Road, Lanzhou 730000, China. E-mail addresses: [email protected] (Y. Peng), [email protected] (G. Liu).

1

ACS Paragon Plus Environment

The Journal of Physical Chemistry 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Abstract Organolead halide perovskite has recently emerged as a star material for various photoelectronic devices owing to its excellent optical and electronic properties. However, it is challenging to develop a perovskite-based photodetector with response across UV-Vis-NIR spectrum due to the lack of absorption in NIR region for perovskite materials. Herein, we report a broadband photodetector based on MAPbI3/SnPc heterostructure with mutual-complementary absorption spectra, extending the photoresponse from UV-Vis to NIR region because of the dominant absorption of the SnPc. The ultralow dark current of ~0.01 nA is obtained and the ultrahigh photosensitivity is up to 105, which is attributed to the high dark resistance and the high electron injection barrier of the heterostructure, and the enhanced photoresponse by the heterostructure architecture. The outstanding sensitivity of our broadband photodetector can be comparable or superior than that of some inorganic, organic, and perovskite photodetectors reported previously. This work provides a route to designing high-performance broadband photodetectors with low noise and high sensitivity.

2


Page 2 of 22

Page 3 of 22 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


1. Introduction A photodetector is an optoelectronic functional device that converts optical signals into electrical signals, which are widely used in industry and science fields, including environmental monitoring, optical communications, day- and night-time surveillance, and chemical/biological sensing 1-4. At present, most of the research on photodetectors focuses on specific wavelengths or narrowband spectra: ultraviolet detectors, visible light detectors and infrared light detectors 5-7. Narrowband spectral photodetectors can only meet specific light detection needs. Broadband spectral photodetectors can achieve light detection from ultraviolet (UV) to visible (Vis) and even to near-infrared (NIR), so that a single device can meet broadband and narrowband photodetection simultaneously. However, broadband absorbing materials with good optoelectronic properties are rare, which have greatly restricted the development of the broadband photodetectors. In order to obtain broadband photodetectors, researchers usually use the methods that mix multiple materials to get a broadband photoresponse, such as planar heterojunction, bulk heterojunction and hybrid planar-bulk heterojunction

8-10.

Although these methods have worked, meanwhile, they will undoubtedly increase the complexity of the preparation process and lower device reliability. Recently, organic-inorganic hybrid perovskites (MAPbX3, X = Cl, Br, I) have become a kind of star material, and researchers have made a lot of achievements11-13. This is mainly attributed to the superior electrical and optical properties of hybrid perovskites, such as broad spectral absorption across UV to the entire visible region, high absorption efficiency, appropriate direct bandgap, high carrier mobility, small exciton binding energy, long range carrier diffusion length as well as simple and inexpensive preparation methods 14-16. So far, the most popular research on perovskites mainly focused on solar cells and have made great progress, and power conversion efficiency (PCE) has exceeded 20%

17-19.

Indeed, it is also promising to apply

perovskite with excellent optoelectronic properties to photodetectors, and the researchers have achieved some results, but the progress is relatively slow, and there are still many problems to be solved. In this regard, the researchers have made various kinds of effort. Hua-Rong Xia et al. used CH3NH3PbI3/TiO2 structure to improve the 3



response speed and switch current ratio of the device 20; Dong-Ho Kang and co-workers emploited MoS2 and hybrid perovskite heterojunction to enable photodetection and the photoresponsivity and specific detectivity of the device have been greatly improved 21; Shan Chen's team obtained a flexible broadband photodetector across UV-Vis-NIR spectral region through the combination of perovskite and polymer materials 22. It can be seen that most of the current perovskite photodetectors are based on perovskite/inorganic composites, a few photodetectors using perovskites and polymers as light absorbing layers, as well as some active layers of perovskite photodetectors coexisted with inorganic and organic materials 12, 23. Unfortunately, inorganic materials or their nanomaterials usually involve complex preparation processes, expensive materials and equipment, which severely limit the practical application of the perovskite/inorganic material based photodetectors. In addition, inorganic materials are not like organic materials that have good compatibility with flexible substrates, which is an unfavorable aspect of the development of flexible photodetectors. For the perovskite/polymer based photodetectors, their advantage is the fabrication process is simple, and they usually can be prepared by a solution method. However, this approach will result in a variety of undesired problems, such as the upper layer of the solution will destroy the integrity of the underlayer film, the difficulty in controlling the quality of the film, and the poor uniformity and repeatability of the device. Faced with the above problems, organic phthalocyanine materials are superior to inorganic semiconductor materials in many respects, such as a wide variety, good light absorption characteristics, simple preparation and purification processes, etc. 24-25. In recent years, organic photodetectors have the advantage of low production cost, mechanical flexibility, large area preparation and light weight, which have attracted wide attention of researchers

26-28.

Besides, organic phthalocyanine materials can be fabricated by

vacuum evaporation, which can better quantify various parameters of device, improve device repeatability and reduce variation between device batches. In this paper, we report a broadband photodetector based on MAPbI3/SnPc heterostructure with complementary spectrum, achieving an ultra-wide photoresponse over the UV-Vis-NIR regime. Considering the high dark resistance and effect of the heterostructure, the 4


Page 4 of 22

Page 5 of 22 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


photodetector have realized ultrahigh sensitivity via enhancement of absorption spectrum extension, excitons dissociation, charge carrier transport and so on. 2. Experimental Section 2.1 Materials and devices fabrication All the raw materials and reagents were purchased from commercial sources, and used as received. The MAI was synthesized in our laboratory. Fig.1a presents the basic photodetector configuration. The heavily doped p-type silicon (p+-Si) wafers with 1000 nm thick thermally grown SiO2 layer were used as the substrates. The Si substrates were firstly cleaned with piranha solution (volume mixing ratio: H2SO4:H2O2 = 7:3) for 2 hours, and ultrasonically cleaned by acetone, ethanol, and deionized water for 10 minutes respectively, and then dried in a vacuum oven for 20 minutes at 60 ℃. Whereafter, these substrates were treated by UV-ozone for 20 minutes. Next, MAPbI3 was synthesized by mixing MAI and PbI2 at 1:1 equimolar ratio in N,Ndimethylformamide (DMF), stirring for 2 hours at 60 °C. ~350 nm thick MAPbI3 film was spin-coated onto the substrates at 600 rpm for 6 s and 2000 rpm for 42 s, and then annealing at 100 °C for 1 hour in a vacuum oven (See Fig. S1 in Supporting Information). Subsequently, 50 nm thick SnPc film was deposited by vacuum thermal evaporation and 40 nm thick Au source/drain electrodes were thermally deposited on the heterostructured active layers, which defined a channel of 50 μm /2 mm length/width (L/W) via a shadow mask. During the physical vapor deposition, the vacuum degree of the chamber was kept below 1.0×10-3 Pa and the deposition rates were maintained at the value of 0.017-0.153 Å/s, which was monitored by a quartz crystal oscillator. 2.2 Measurements and characterizations When the device fabrication was finished, we performed all the measurements immediately using a semiconductor device characterization system at room temperature under different conditions of darkness and illumination. We selected nine laser diodes with fixed wavelengths (405, 450, 532, 650, 780, 808, 830, 850 and 980 nm) across 5



Page 6 of 22

UV-Vis-NIR spectra as the light sources to characterized the photoelectronic property, of which light power densities were varied by different neutral light filters. These thin films of SnPc (50 nm), MAPbI3 (350 nm) and SnPc (50 nm)/MAPbI3 (350 nm) were prepared on the cleaned quartz substrates by vacuum thermal evaporation and spincoated methods, and then used to measure the absorption spectra by Shimadzu UV2600 UV-Vis spectrophotometer. The morphology and elemental information of the films were investigated by scanning electron microscopy (SEM, JSM-5600LV and Apreo S). X-ray diffraction (XRD, Rigaku D/max-2400) was employed to determinate the structure of these films. Ultraviolet photoelectron spectroscopy (UPS, Axis Ultra DLD) was used to investigate the energy levels of MAPbI3 and SnPc films. 2.3 Figures of merit for photodetectors Five figures of merit were used to assess the performance of the MAPbI3/SnPc heterostructure photodetector, namely photocurrent (Iph), photoresponsivity (R), photosensitivity (P), specific detectivity (D*) and external quantum efficiency (EQE)8, 10, 29-30.

Iph is the difference between Idark and Iill as follows (1)

I ph = I ill - I dark

where Idark and Iill are the output current at the same applied voltage in darkness and under illumination. R is an essential parameter for a photodetector, representing the photoelectric conversion capability, and is given as R=

I ph Popt

=

I ill - I dark Pinc A

(2)

where Popt is the incident light power on the channel of the device, Pinc is the incident light intensity, and A is the effective irradiated area of the device. P is defined as the ratio of Iph to Idark, characterizing the ability of signals to suppress noises, which can express as

P=

I ph I dark

=

I ill - I dark I dark

(3)

6


Page 7 of 22 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Another two significant figures of merit are D* and EQE, which are employed to describe the production efficiency from incident photons to collected electrons and the ability to detect the minimum optical signal, respectively. EQE and D* can be written as D* =

RA1/ 2

( 2qI )

(4)

1/ 2

dark

EQE =

hc R q

(5)

where q is the electron charge, h is the Planck’s constant, c is the speed of light in vacuum, and λ is the incident light wavelength. It is noted that there are three contributions to the total noise that limit D*: Johnson noise, thermal fluctuation noise and shot noise, where the shot noise from the dark current was commonly considered to be the major contributor to the total noise in this case8. 3. Results and discussion The configuration of perovskite/SnPc heterstructured photodetector is present in Fig. 1a, the corresponding SEM cross-sectional image is shown in Fig. S1 and the control device structures can be seen in Fig. S2. Among them, the structure of deviceA is p+-Si/SiO2/MAPbI3/Au&Au, device-B is p+-Si/SiO2/SnPc/MAPbI3/Au&Au, device-C

is

p+-Si/SiO2/MAPbI3/SnPc/Au&Au

and

device-D

is

p +-

Si/SiO2/MAPbI3/Au&Au/SnPc. The comparison between device-A and other devices indicates the role of SnPc layer in the active layer, and the comparison of devices-B, C and D reflects the effect of SnPc layer on device performance at different positions of devices. Finally, the experimental results show that device-C has the best broadband photosensitive performance. Therefore, we identified device-C as the experimental device and the detailed results will be discussed later. The surface morphology of MAPbI3, MAPbI3/SnPc and SnPc films are characterized by SEM image, as shown in Fig. 1b, c and Fig. S3. The perovskite film is identified to have a biggish crystal grain size of ~1 μm, indicative of a better crystallinity. After SnPc film covers onto MAPbI3 layer, of which the surface become 7



Page 8 of 22

dense and flat. We deduce that SnPc film will passivate the defects of perovskite, facilitating carrier transport, and act as an electrode buffer layer meanwhile. Fig. 1d shows the optical absorption spectra of the perovskite, SnPc and perovskite/SnPc films. The spectrum of perovskite film exhibits a broad spectral absorption from UV to the whole Vis regions and the absorption edge near the wavelength of ~800 nm, which is consistent with the bandgap of MAPbI3 31. The SnPc film has a dominant absorption band peaked at 895 nm, loacated outside the absorption spectrum of perovskite film. Therefore, the perovskite/SnPc bilayer film presents a mutual-complementary absorption with the absorption edge extend to >1000 nm, making it a great candidate for the fabrication of UV-Vis-NIR broadband photodetectors. The corresponding XRD patterns of the SnPc, perovskite and perovskite/SnPc films are depicts in Fig. 1e. The SnPc film has two peaks corresponding to the metastable (α type) form, indicating that a polycrystalline SnPc film is formed32. Both MAPbI3 and MAPbI3/SnPc heterstructure films have similar X-ray diffraction feature, and the strong characteristic peaks at 14.06°, 28.37° and 31.82° can be assigned to the (110), (220) and (310) crystallographic planes of MAPbI3, respectively

22, 33-34.

This

results reflects that the perovskite formed polycrystalline films, which possess the expected tetragonal crystal structure with high crystallinity. The SnPc film has no significant effect on the crystalline structure of perovskite film except for a weak peak from SnPc layer. Moreover, the energy dispersive spectrometer analysis has presented element distribution of carbon, nitrogen, lead, iodine and tin (Fig. S4). Combined with XRD results of the films, the as-fabricated MAPbI3 and MAPbI3/SnPc thin films were further confirmed. The schematic energy levels diagram of the heterostructure is shown in Fig. 1f. The energy levels of MAPbI3 and SnPc are estimated from UPS spectra and the transformed Kubelka-Munk spectra. The detailed calculation process can be seen in Fig. S5. The perovskite film is responsible for the absorption of UV-Vis wavelength region while the SnPc film dominates in the NIR region. In the dark, the high electron barrier at Au/SnPc interface blocks the dark electron injection on one hand, and on the other 8


Page 9 of 22 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


hand the high dark resistance of the heterostructure suppressed dark current, so a very small dark current around 0.03 nA is obtained. Under UV-Vis light illumination, excitons or electron-hole pairs are generated in the perovskite layer, and then they dissociate into free electrons and holes by the applied bias or heterojunction interfaces. Similarly, under NIR light illumination, excitons are generated in the SnPc layer instead, and some of them diffuse to the heterojunction interfaces which helps separate the electron and holes and suppress their recombination. Therefore, the enhanced photocurrent is achieved by the heterostructure of perovskite/SnPc. For the optoelectrical properties study of the photodetector, we intentionally select nine monochromatic laser diodes with specific wavelengths of 405, 450, 532, 650, 780, 808, 830, 850 and 980 nm from UV-Vis to NIR region as the light sources. Fig.2a shows the dark current dependent on the applied voltage of the photodetector without illumination, which is the result of dozens of statistics on four samples. The very small dark current of ~0.03 nA at -10V is obtained from the heterostructure, which will result in low noise and high photosensitivity for our photodetector. Obviously, such a pAscale dark current can endow the photodetector with ability to detect weak light. Under illumination of each wavelength light, the photodetector exhibits obvious photoresponse with similar behavior, showing the typical current-voltage (I-V) characteristics, as shown in Fig. 2 and Fig. S6. The microampere scale photocurrent is recorded for 405, 450, 532 and 650 nm light illumination owning to the excellent light harvest of MAPbI3 in UV-Vis range. Meanwhile, a non-negligible photocurrent enhancement is obtained in the NIR region originated from the absorption extension of SnPc layer, which is also corroborated by the comparison of dark current, photoresponsivity and photosensitivity between the four devices, as shown in Fig. S7. For devices-A~D, the dark current is on the order of ~0.01 nA (~10 pA) with or without SnPc layer, indicating little effect on the dark current of these devices by SnPc layer, which is attributed to the small conductivity of SnPc layer along with perovskite layer under dark condition. Compared with device-A, devices-B and C can enhance the photoexcitons dissociation and NIR-sensitivity by the heterostructures, thus obtaing greater photoresponsivity and photosensitivity. In addition, the SnPc layer on the 9



MAPbI3 layer acts as an electrode buffer-layer, which both modifies the electrodes and fills the pinholes of the MAPbI3 film, thereby enhancing the charge carriers transport. While the SnPc layer in device-B is located below the MAPbI3 layer which is probably destroyed by the MAPbI3 solvent, and thus the performance of the device-B is slightly lower than that of the device-C. The inferior photoresponse of device-D is attributed to the bottom contact structure of SnPc film and Au electrodes, resulting in a greater contact resistance in the bottom contact structure. Therefore, device-C exhibits the best photosensitive performance. Fig. 3a shows the drain-source current under different wavelengths light illumination from 405 nm to 980 nm at a fixed light intensity power of 20 mWcm-2. It is observed that obvious photocurrents were obtained for all these wavelengths light illumination, indicating a broadband photoresponse in the UV-Vis-NIR wide region of our photodetector. To further characterize the photodetection capability of this photodetector quantitatively, P, R, D*, EQE and response time, which are extracted from I-V curves, are used to evaluate the performance of the broadband photodetector. Table S1 summarizes all key metrics of the MAPbI3/SnPc heterostructure based photodetector under all selected UV–Vis–NIR wavelength illuminations. Fig. 3b shows the wavelength-dependent responsivity of the photodetector at an applied voltage of – 10 V under a constant illumination intensity of 0.013 mWcm-2, presenting decreased responsivity from 665.75 mAW-1 for 405 nm to 0.72 mAW-1 for 980 nm, which are probably related to the superior ablity of excitons dissociation, transport and collection of perovskite than those of SnPc. The ultra-wide band photoresponsivity is obtained due to the complementary absorption spectrum of perovskite and phthalocyanine compound. Fig. 3c displays the dependence of the photocurrent and photoresponsivity on the incident light intensity under 405 nm light illumination. Along the increased incident light intensity, the photocurrent increased while the responsivity decreased by a sublinear behavior and the similar variation is exhibited for other wavelengths light illumination, which has been frequently observed in some organic and inorganic photodetectors 8, 10, 35-36. The relationship of Iph and R as a function of Pinc could be fitted 10


Page 10 of 22

Page 11 of 22 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


by the power laws of Iph ∝Pincα and R∝Pincβ-1 36-37, with the extracted values of α = β = 0.80, which are obviously greater than those of photodetectors reported recently 8, 36, 38.

The values of α and β reflect the complex mechanism of photocarriers separation,

trapping, and recombination inside the MAPbI3/SnPc heterostructure photodetector. The higher α and β denote the efficient excitons dissociation, lower trapping ratios and charge recombination. For a photodetector, the low dark current and high photocurrent is critical to the photosensitivity, so we extracted the wavelength-dependent photosensitivity from Fig. 2a and Fig. 3a at a settled voltage of -10V and light intensity of 20 mWcm-2, as shown in Fig. 3d. A broadband photosensitive photodetector is successfully realized with outstanding P more than 103 in UV-Vis region and beyond 10 in 780-850 nm NIR region, up to the maximum of >104 for 405-532 nm excitation. Furthermore, a 2D contour color map of wavelength & voltage dependent Pmax clearly reveals the excellent broadband photosensitivity of the photodetector, where the Pmax is more than 105, as shown in Fig. 3e. Specific detectivity (D*) and external quantum efficiency (EQE) were also adopted to evaluate the broadband photodetection performance of our photodetector. Fig. 3f shows the dependence of D* and EQE on the wavelength at a fixed light intensity of 0.013 mWcm-2 and applied voltage of -10V. The maximum D* and EQE of 6.45 × 1012 Jones and 204.22% were obtained at 405 nm, while the minimum values of 6.98 × 109 Jones and 0.09% were at 980nm. All the photosensitive

parameters

above

demonstrated

the

preeminent

broadband

photodetection performance over the UV-Vis-NIR spectrum of our photodetector based on MAPbI3/SnPc heterostructure, most of which are comparable or superior to those of organic and inorganic photodetectors published recently 5, 21-22. Reliable and fast responses to light illumination are vital to high-performance photodetectors. Fig. 4a-c and Fig. S8 shows the time-dependent response under different wavelength irradiation from 405 nm to 980 nm running in a 20 s period for 7.5 cycles, from which we can clearly observed that the currents varies regularly with the periodic illumination. Furthermore, to characterize the cycle stability of our device, we measured the photoresponse for a long time of 105 cycles under 405, 650 and 808 nm illumination, as shown in Fig. S9. There is almost no attenuation for the 11



Page 12 of 22

photocurrent of our device, indicating a stable and reproducible on/off switching for multiple cycles in the UV-Vis-NIR range. We also investigated temporal photoresponse behavior of the photodetector under different light intensities and applied voltages, as show in Fig. 4h and i. The photocurrent changed rapidly with the light on/off and varied regularly with the altering light intensities and voltages, manifesting a favourable dynamic response characters by adjusting the light power and applied voltage. Moreover, the transient responsees were recorded at a high frequency of 300 Hz, demonstrating a fast photoswitching behavior, as shown in Fig. 4d-f. The rise time and fall time were extracted to be 0.39 and 0.53 ms, respectively, just like Fig. 4g displayed. The high response speed of our MAPbI3/SnPc heterostructure photodetector has been superior to that of numerous organic and inorganic photodetectors in the literature 15, 20, 39.

It should be noted that the current values of response time are limited by the present

experimental conditions (the mechanical chopper). In order to further meet the practical application, the time-stability, uniformity and reproducibility of the MAPbI3/SnPc heterojunction photodetector is important issues that should be considered. Fig. 5a shows the time-dependent responsivity and photosensitivity of the photodetector under 405 nm light illumination in the ambient environment. It is observed that a slight fluctuation occurred in the first 7 days and a degradation appeared in the 10th day, which may result from the moisture and oxygen corrosion to the perovskite layer 12-13, 33. Moreover, the uniformity of the samples was also measured by recording the responsivity under different wavelengths illumination, as shown in Fig. 5b. We can see that the distribution of normalized R of the majority of samples showed relatively small fluctuations in the UV-Vis-NIR range. In addition, the reproducibility of the photodetector was investigated by comparing the change of normalized R from four batches of samples under 405 nm irradiation, as shown in Fig. 5c. The results indicate that a high reproducibility is achieved for the MAPbI3/SnPc heterostructure photodetector. 4. Conclusions In summary, we have demonstrated a broadband photodetector based on MAPbI3/SnPc heterostructure

with

mutual-complementary

absorption

12


spectra,

realizing

a

Page 13 of 22 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


photoresponse from UV-Vis to NIR region. Because of the dominant absorption of the SnPc in NIR region, the device response spectrum has extended to NIR range, which made up for the lack of absorption of perovskite in NIR range. The broadband photodetector shows an ultralow dark current of ~0.01 nA and the ultrahigh photosensitivity of ~105, which is attributed to that the high dark resistance of the active films and the high electron injection barrier of the heterostructure suppressed the dark current, and the MAPbI3/SnPc heterostructure enhanced the photoresponse. The remarkable sensitivity of our broadband photodetector can be comparable or superior than that of some inorganic, organic, and perovskite materials based broadband photodetectors in the literature. This study could be a beacon to develop highperformance broadband photodetectors with low noise and high sensitivity for potential applications in the UV-Vis-NIR photodetection area.

13



Supporting Information Key photosensitive parameters of the broadband photodetector; SEM image of the MAPbI3/SnPc heterostructure; Reference device configurations; SEM image of SnPc film; Energy dispersive spectrometer analysis of the films; UPS and transformed Kubelka-Munk spectra of the films; I-V characteristics of the broadband photodetector for other wavelengths; Performance comparison of device-A~D; Time-dependent photoresponse of the broadband photodetector for other wavelengths; Longtimedependent photoresponse of the broadband photodetector. Acknowledgments This work was supported by the National Key R&D Program of China (Grant No. 2016YFF0203605) and the Natural Science Foundation of Zhejiang Province (Grant No. LY18F050009). References 1.

Konstantatos, G.; Howard, I.; Fischer, A.; Hoogland, S.; Clifford, J.; Klem, E.; Levina, L.; Sargent,

E. H., Ultrasensitive Solution-Cast Quantum Dot Photodetectors. Nature 2006, 442, 180. 2.

Mueller, T.; Xia, F.; Avouris, P., Graphene Photodetectors for High-Speed Optical

Communications. Nature photonics 2010, 4, 297. 3.

Gong, X.; Tong, M.; Xia, Y.; Cai, W.; Moon, J. S.; Cao, Y.; Yu, G.; Shieh, C.-L.; Nilsson, B.;

Heeger, A. J., High-Detectivity Polymer Photodetectors with Spectral Response from 300 Nm to 1450 Nm. Science 2009, 325, 1665-1667. 4.

Yao, Y.; Liang, Y.; Shrotriya, V.; Xiao, S.; Yu, L.; Yang, Y., Plastic near‐Infrared Photodetectors

Utilizing Low Band Gap Polymer. Advanced Materials 2007, 19, 3979-3983. 5.

Zheng, W.; Lin, R.; Ran, J.; Zhang, Z.; Ji, X.; Huang, F., Vacuum-Ultraviolet Photovoltaic Detector.

ACS nano 2018, 12, 425-431. 6.

Lin, H.; Xu, Z.; Zhang, L.; Yang, X.; Ju, Q.; Xue, L.; Zhou, J.; Zhuo, S.; Wu, Y.,

Diketopyrrolopyrrole Derivative Functionalized Graphene for High Performance Visible-Light Photodetectors. New J. Chem. 2017, 41, 4302-4307. 7.

Liang, F. X.; Wang, J. Z.; Li, Z. P.; Luo, L. B., Near‐Infrared‐Light Photodetectors Based on

One‐Dimensional Inorganic Semiconductor Nanostructures. Advanced Optical Materials 2017, 5, 1700081. 8.

Huang, F.; Wang, X.; Xu, K.; Liang, Y.; Peng, Y.; Liu, G., Broadband Organic Phototransistor with

High Photoresponse from Ultraviolet to near-Infrared Realized Via Synergistic Effect of Trilayer 14


Page 14 of 22

Page 15 of 22 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Heterostructure. Journal of Materials Chemistry C 2018, 6, 8804-8811. 9.

Zhao, F.; Luo, X.; Liu, J.; Du, L.; Lv, W.; Sun, L.; Li, Y.; Wang, Y.; Peng, Y., Toward High

Performance Broad Spectral Hybrid Organic–Inorganic Photodetectors Based on Multiple Component Organic Bulk Heterojunctions. Journal of Materials Chemistry C 2016, 4, 815-822. 10. Huang, F.; Li, Y.; Xia, H.; Zhang, J.; Xu, K.; Peng, Y.; Liu, G., Towards High Performance Broad Spectral Response Fullerene Based Photosensitive Organic Field-Effect Transistors with Tricomponent Bulk Heterojunctions. Carbon 2017, 118, 666-674. 11. Ansari, M. I. H.; Qurashi, A.; Nazeeruddin, M. K., Frontiers, Opportunities, and Challenges in Perovskite Solar Cells: A Critical Review. Journal of Photochemistry and Photobiology C: Photochemistry Reviews 2018, 35, 1-24. 12. Wang, X.; Li, M.; Zhang, B.; Wang, H.; Zhao, Y.; Wang, B., Recent Progress in Organometal Halide Perovskite Photodetectors. Organic Electronics 2017. 13. Asghar, M.; Zhang, J.; Wang, H.; Lund, P., Device Stability of Perovskite Solar Cells–a Review. Renewable and Sustainable Energy Reviews 2017, 77, 131-146. 14. Zheng, L.; Zhang, D.; Ma, Y.; Lu, Z.; Chen, Z.; Wang, S.; Xiao, L.; Gong, Q., Morphology Control of the Perovskite Films for Efficient Solar Cells. DTr 2015, 44, 10582-10593. 15. Wang, J.; Liu, F.; Wang, G.; Wang, L.; Jiang, C., Novel Organic-Perovskite Hybrid Structure Forward Photo Field Effect Transistor. Organic Electronics 2016, 38, 158-163. 16. Turren-Cruz, S.-H.; Saliba, M.; Mayer, M. T.; Juárez-Santiesteban, H.; Mathew, X.; Nienhaus, L.; Tress, W.; Erodici, M. P.; Sher, M.-J.; Bawendi, M. G., Enhanced Charge Carrier Mobility and Lifetime Suppress Hysteresis and Improve Efficiency in Planar Perovskite Solar Cells. Energy Environ. Sci. 2018, 11, 78-86. 17. Arora, N.; Dar, M. I.; Hinderhofer, A.; Pellet, N.; Schreiber, F.; Zakeeruddin, S. M.; Grätzel, M., Perovskite Solar Cells with Cuscn Hole Extraction Layers Yield Stabilized Efficiencies Greater Than 20%. Science 2017, eaam5655. 18. Shin, S. S.; Yeom, E. J.; Yang, W. S.; Hur, S.; Kim, M. G.; Im, J.; Seo, J.; Noh, J. H.; Seok, S. I., Colloidally Prepared La-Doped Basno3 Electrodes for Efficient, Photostable Perovskite Solar Cells. Science 2017, 356, 167-171. 19. Jeon, N. J.; Na, H.; Jung, E. H.; Yang, T.-Y.; Lee, Y. G.; Kim, G.; Shin, H.-W.; Seok, S. I.; Lee, J.; Seo, J., A Fluorene-Terminated Hole-Transporting Material for Highly Efficient and Stable Perovskite Solar Cells. Nature Energy 2018, 3, 682. 20. Xia, H.-R.; Li, J.; Sun, W.-T.; Peng, L.-M., Organohalide Lead Perovskite Based Photodetectors with Much Enhanced Performance. Chem. Commun. 2014, 50, 13695-13697. 21. Kang, D. H.; Pae, S. R.; Shim, J.; Yoo, G.; Jeon, J.; Leem, J. W.; Yu, J. S.; Lee, S.; Shin, B.; Park, J. H., An Ultrahigh‐Performance Photodetector Based on a Perovskite–Transition‐Metal‐Dichalcogenide Hybrid Structure. Advanced Materials 2016, 28, 7799-7806. 22. Chen, S.; Teng, C.; Zhang, M.; Li, Y.; Xie, D.; Shi, G., A Flexible Uv–Vis–Nir Photodetector Based on a Perovskite/Conjugated‐Polymer Composite. Advanced Materials 2016, 28, 5969-5974. 23. Ahmadi, M.; Wu, T.; Hu, B., A Review on Organic–Inorganic Halide Perovskite Photodetectors: Device Engineering and Fundamental Physics. Advanced Materials 2017, 29, 1605242. 24. Mishra, A.; Bäuerle, P., Small Molecule Organic Semiconductors on the Move: Promises for Future Solar Energy Technology. Angew. Chem. Int. Ed. 2012, 51, 2020-2067. 25. Henson, Z. B.; Müllen, K.; Bazan, G. C., Design Strategies for Organic Semiconductors Beyond the Molecular Formula. Nat. Chem. 2012, 4, 699. 15



26. Zhang, H.; Jenatsch, S.; De Jonghe, J.; Nüesch, F.; Steim, R.; Véron, A. C.; Hany, R., Transparent Organic Photodetector Using a near-Infrared Absorbing Cyanine Dye. Scientific reports 2015, 5, 9439. 27. Liu, X.; Lee, E. K.; Kim, D. Y.; Yu, H.; Oh, J. H., Flexible Organic Phototransistor Array with Enhanced Responsivity Via Metal–Ligand Charge Transfer. ACS applied materials & interfaces 2016, 8, 7291-7299. 28. Li, F.; Chen, Y.; Ma, C.; Buttner, U.; Leo, K.; Wu, T., High-Performance near-Infrared Phototransistor Based on N-Type Small-Molecular Organic Semiconductor. Advanced Electronic Materials 2016. 29. Huang, F.; Li, Y.; Xu, K.; Lv, W.; Xu, S.; Peng, Y.; Wang, Y.; Liu, G., Improved Performance of Lead Phthalocyanine Phototransistor by Template Inducing Effect Based on Optimized-Thickness Copper Phthalocyanine Layers. Synthetic Metals 2017, 234, 100-105. 30. Leung, S. F.; Ho, K. T.; Kung, P. K.; Hsiao, V. K.; Alshareef, H. N.; Wang, Z. L.; He, J. H., A Self‐Powered and Flexible Organometallic Halide Perovskite Photodetector with Very High Detectivity. Advanced Materials 2018, 30, 1704611. 31. Murali, B.; Saidaminov, M. I.; Abdelhady, A. L.; Peng, W.; Liu, J.; Pan, J.; Bakr, O. M.; Mohammed, O. F., Robust and Air-Stable Sandwiched Organo-Lead Halide Perovskites for Photodetector Applications. Journal of Materials Chemistry C 2016, 4, 2545-2552. 32. Hijikata, Y.; Inoue, J.; Yamashita, M., Film Structures and Electro-Optic Properties of Multilayer Organic Thin Film Semiconductors. Japanese Journal of Applied Physics 2008, 47, 513. 33. Deng, W.; Zhang, X.; Huang, L.; Xu, X.; Wang, L.; Wang, J.; Shang, Q.; Lee, S. T.; Jie, J., Aligned Single‐Crystalline Perovskite Microwire Arrays for High‐Performance Flexible Image Sensors with Long‐Term Stability. Advanced Materials 2016, 28, 2201-2208. 34. Kwon, K. C.; Hong, K.; Van Le, Q.; Lee, S. Y.; Choi, J.; Kim, K. B.; Kim, S. Y.; Jang, H. W., Inhibition of Ion Migration for Reliable Operation of Organolead Halide Perovskite‐Based Metal/Semiconductor/Metal Broadband Photodetectors. Advanced Functional Materials 2016, 26, 42134222. 35. Lim, S.; Um, D.-S.; Ha, M.; Zhang, Q.; Lee, Y.; Lin, Y.; Fan, Z.; Ko, H., Broadband Omnidirectional Light Detection in Flexible and Hierarchical Zno/Si Heterojunction Photodiodes. Nano Research 2017, 10, 22-36. 36. Buscema, M.; Groenendijk, D. J.; Blanter, S. I.; Steele, G. A.; Van Der Zant, H. S.; CastellanosGomez, A., Fast and Broadband Photoresponse of Few-Layer Black Phosphorus Field-Effect Transistors. Nano letters 2014, 14, 3347-3352. 37. Li, Z.; Gao, F.; Greenham, N. C.; McNeill, C. R., Comparison of the Operation of Polymer/Fullerene, Polymer/Polymer, and Polymer/Nanocrystal Solar Cells: A Transient Photocurrent and Photovoltage Study. Advanced Functional Materials 2011, 21, 1419-1431. 38. Hu, X.; Zhang, X.; Liang, L.; Bao, J.; Li, S.; Yang, W.; Xie, Y., High‐Performance Flexible Broadband Photodetector Based on Organolead Halide Perovskite. Advanced Functional Materials 2014, 24, 7373-7380. 39. Zou, C.; Xi, Y.; Huang, C. Y.; Keeler, E. G.; Feng, T.; Zhu, S.; Pozzo, L. D.; Lin, L. Y., A Highly Sensitive Uv–Vis–Nir All‐Inorganic Perovskite Quantum Dot Phototransistor Based on a Layered Heterojunction. Advanced Optical Materials 2018, 6, 1800324.

16


Page 16 of 22

Page 17 of 22 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Figures and captions

Fig.

1

Design

philosophy

of

the

broadband

photodetector

based

on

perovskite/phthalocyanine heterostructure of MAPbI3/SnPc. (a) The schematic configuration of the device. The SEM images of (b) MAPbI3 and (c) MAPbI3/SnPc thin films. (d) The UV-Vis-NIR absorption spectra and (e) XRD patterns of SnPc, MAPbI3 and MAPbI3/SnPc thin films. (f) The energy band diagram of the broadband photodetector based on MAPbI3/SnPc heterostructure.

17



Fig. 2 The typical I-V characteristics of the broadband photodetector in the dark and under different monochromatic light illumination of 405, 650 and 808 nm wavelengths with various incident light intensities, respectively. (a) Statistical distribution of dark current, (b) under near-UV light illumination of 405 nm, (c) under visible light illumination of 650 nm and (d) under NIR light illumination of 808 nm.

18


Page 18 of 22

Page 19 of 22 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Fig. 3 The photosensitive performance of the broadband photodetector. (a) The I-V characteristics of the device in the dark and at a fixed incident light intensity of 20 mW/mm2 for different wavelength irradiations over UV-Vis-NIR region. (b) The dependence of photoresponsivity on wavelength under 0.013 mW/cm2 light intensity illumination at -10 V. (c) The incident light intensity dependent photoresponsivity and photocurrent for 405 nm light illumination. (d) The dependence of photosensitivity on wavelength under 20 mW/cm2 light intensity illumination at -10 V. (e) 2D contour color map of the maximum photosensitivity as a function of wavelength and voltage. (f) The dependence of specific detectivity and external quantum efficiency on the wavelength under 0.013 mW/cm2 light intensity illumination at -10 V.

19



Fig. 4 The time-dependent photoresponse of the broadband photodetector under 405, 650 and 808 nm light illumination to periodic on/off operation: (a)-(c) long period test and (d)-(f) transient response test, (g) the extraction of the rise/fall time, (h) under different incident light intensity illuminations and (i) at different applied voltages.

20


Page 20 of 22

Page 21 of 22 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Fig. 5 The device time-stability, uniformity and reproducibility measurements of the MAPbI3/SnPc

photodetector.

(a)

The

variation

of

photosensitivity

and

photoresponsivity with the time exposed to the ambient environment. (b) The distribution of normalized photoresponsivity of the device in same batch for different wavelengths from UV-Vis to NIR range. (c) The distribution of normalized photoresponsivity of the device in four batches of samples.

21



TOC Graphic

22


Page 22 of 22

Towards Ultrahigh Sensitivity and UV-Vis-NIR Broadband Response

Recommend Documents