High-performance Self-powered Photodetector Research Articles

Piezo-phototronic effect modulated self-powered UV/visible/near-infrared photodetectors based on CdS:P3HT microwires

A kind of high-performance self-powered broad-band photodetectors throughout UV/visible/near-infrared wavelengths have been fabricated based on CdS:P3HT microwires. The fabricated devices exhibit fast responses and excellent sensitivities to UV/visible/near infrared light illumination at zero bias. Together with the fast response and high sensitivity, the photocurrent under UV illumination can be increased to more than 330% when applying a 0.67% tensile strain under the [001] direction point of CdS microwire contacting with P3HT. This enhancement through the piezo-phototronic effect can be attributed to the increase of built-in field at the interface of p-n junction, which is favorable to the separation of photogenerated electron-hole pairs in CdS and P3HT. In comparison, the photocurrent under UV illumination can be decreased to ~ 20% when applying a 0.67% tensile strain under the [001¯] direction point of CdS microwire which contacts with P3HT. This research not only focuses on the photoelectric property of organic-inorganic hybrid semiconductors, but also combines it with piezoelectric effect to modulate the performance of optoelectronic devices made of piezoelectrical semiconducting materials.

High-performance self-powered UV-Vis-NIR photodetectors based on horizontally aligned GaN microwire array/Si heterojunctions

High-performance self-powered photodetectors based on GaN microwire array/Si heterojunctions show a broadband photoresponse with high EQE, responsivity and detectivity at zero bias.

Sb2S3/Spiro-OMeTAD Inorganic-Organic Hybrid p-n Junction Diode for High Performance Self-Powered Photodetector.

Organic-inorganic hybrid diodes are very promising for solution processing, low cost, high performance optoelectronic devices. Here, we report a high quality p-n heterojunction diode composed of n-type inorganic Sb2S3 and p-type organic 2,2',7,7'-tetrakis-(N,N-di-p-methoxyphenylamine)-9,9'-spirobifluorene (spiro-OMeTAD) with a rectification ratio of ∼102 at an applied bias of 1 V. On illumination with visible light (470 nm, 1.82 mW/cm2), the current value in our device becomes 8 × 102 times that of its dark value even at a zero bias condition. The estimated responsivity value at zero bias is 0.087 A/W which is so far the highest reported for any organic-inorganic hybrid photodiode, to the best of our knowledge. It also exhibits a fast photoresponse time of <25 ms (instrumental limit). More importantly, our device can also detect visible light with power density as low as 8 μW/cm2 with a photocurrent density of 1.2 μA/cm2 and a photocurrent to dark current ratio of more than 8. We also demonstrate that the values of responsivity, short circuit current, and open circuit voltage of the photodetector can be improved significantly using a thin layer of TiO2 hole-blocking layer. These findings suggest Sb2S3/spiro-OMeTAD heterojuncton as a promising candidate for efficient self-powered low visible light photodetector.

Coupling of photoelectric and triboelectric effects as an effective approach for PZT-based high-performance self-powered ultraviolet photodetector

A high-performance self-powered UV photodetector (UV-SPPD) using a PZT film was fabricated and characterized. It has a dual sensing mechanism that relies on the joint properties of a photoelectric effect and a triboelectric effect on the surface of the ferroelectric material. The UV-SPPD exhibits excellent responsivity (15mAW−1), large detectivity (2×1010cmHz−1/2 W−1), a fast photo response time (<50ms), and good stability and repeatability. This work creates new opportunities for designing high-performance self-powered UV photodetectors and other tribotronic devices.

High-Performance Self-powered Photodetectors Based on ZnO/ZnS Core-Shell Nanorod Arrays.

In recent years, there is an urgent demand for high-performance ultraviolet photodetectors with high photosensitivity, fast responsivity, and excellent spectral selectivity. In this letter, we report a self-powered photoelectrochemical cell-type UV detector using the ZnO/ZnS core-shell nanorod array as the active photoanode and deionized water as the electrolyte. This photodetector demonstrates an excellent spectral selectivity and a rapid photoresponse time of about 0.04 s. And the maximum responsivity is more than 0.056 (A/W) at 340 nm, which shows an improvement of 180 % compared to detectors based on the bare ZnO nanorods. This improved photoresponsivity can be understood from the step-like band energy alignment of the ZnO/ZnS interface, which will accelerate the separation of photoexcited electron-hole pairs and improve the efficiency of the photodetector. Considering its uncomplicated low-cost fabrication process, and environment-friendly feature, this self-powered device is a promising candidate for UV detector application.

Self-powered and broadband photodetectors based on graphene/ZnO/silicon triple junctions

A self-powered photodetector with ultrahigh sensitivity, fast photoresponse, and wide spectral detectivity covering from 1000 nm to 400 nm based on graphene/ZnO/Si triple junctions has been designed, fabricated, and demonstrated. In this device, graphene serves as a transparent electrode as well as an efficient collection layer for photogenerated carriers due to its excellent tunability of Fermi energy. The ZnO layer acts as an antireflection layer to trap the incident light and enhance the light absorption. Furthermore, the insertion of the ZnO layer in between graphene and Si layers can create build-in electric field at both graphene/ZnO and ZnO/Si interfaces, which can greatly enhance the charge separation of photogenerated electron and hole pairs. As a result, the sensitivity and response time can be significantly improved. It is believed that our methodology for achieving a high-performance self-powered photodetector based on an appropriate design of band alignment and optical parameters can be implemented to many other material systems, which can be used to generate unique optoelectronic devices for practical applications.

A high-performance self-powered broadband photodetector based on a CH3NH3PbI3 perovskite/ZnO nanorod array heterostructure

An FTO/ZnO-nanorod/CH3NH3PbI3/MoO3/Au photodetector exhibited high performance and can achieve self-powered, broadband light detection, high detectivity and responsivity, robust and high stability.

High-performance self-powered perovskite photodetector with a rapid photoconductive response

Here we report the development of a self-powered high-speed perovskite Schottky junction photodiode, which is very important for next-generation electronic devices.

A high-performance self-powered UV photodetector based on SnO2 mesoporous spheres @ TiO2

A novel self-powered UV photodetector (UVPD) based on the photoelectrochemical cell (PECC) has been constructed using the TiO2 coated SnO2 mesoporous spheres (SnO2-MS@TiO2). This self-powered UVPD displays a higher photocurrent density compared to the UVPD with the pure SnO2-MS. By means of external quantum efficiency (EQE), UV-vis absorption, and electrochemical impedance measurements, we scrutinize the intrinsic role of the TiO2 coating layer on the photocurrent enhancement. Under UV irradiation, this UVPD exhibits a high on/off ratio of 11519, a fast rise time of 0.007 s and decay time of 0.006 s, together with the excellent visible-blind characteristic and linear optical signal response. The self-powered photodetector is a promising candidate for application in high-sensitivity and high-speed UVPDs.

High-Performance Organolead Halide Perovskite-Based Self-Powered Triboelectric Photodetector.

We report a MAPbI3-based self-powered photodetector (SPPD). It has a dual sensing mechanism that relies on the joint properties of a photoelectric effect and a triboelectric effect of the perovskite material. Both the photoconductivity and the surface triboelectric density of the MAPbI3-based composite thin film are significantly altered upon solar illumination, which results in considerable reduction of the output voltage. The SPPD exhibits excellent responsivity (7.5 V W(-1)), rapid response time (<80 ms), great repeatability, and broad detection range that extends from UV to visible regions. This work presents a route to designing high-performance self-powered photodetectors from the aspect of materials.

Self-powered n-MgxZn1-xO/p-Si photodetector improved by alloying-enhanced piezopotential through piezo-phototronic effect

A high-performance self-powered ZnO-based photodetector is developed by enhancing piezopotential through alloying with Mg. An n-MgxZn1-xO thin film (x=0.05 and 0.2) with a strong c axis preferred orientation in the wurtzite phase is grown on a p-type Si substrate by magnetron co-sputtering. The piezotronics and piezo-phototronics properties are studied by determining the dependence of electrical and optical characteristics of preferentially orientated MgxZn1-xO thin films on strain. The performance of the self-powered photodetectors increases with Mg content due to the increase of the piezoelectric coefficient by the alloying process, and thus an enhanced piezopotential. In addition, the photosensing results show that the piezo-phototronic effect can boost the output current density and voltage of the self-powered photodetector by more than 100%. The sensitivity of the photodetector with Mg0.20Zn0.80O is over 6-fold greater than that of the photodetector with Mg0.05Zn0.95O. The results demonstrate a strong dependence on Mg content in MgxZn1-xO for the piezo-phototronic effect. The developed material is thus a promising candidate for ultra-high-sensitivity photodetectors.

ZnO homojunction ultraviolet photodetector based on p-type dual-doped film and n-type nanorods

ZnO:(Ag,N)/ZnO p–n homojunction was fabricated by depositing a ZnO:(Ag,N) film on vertically aligned ZnO nanorods (NRs). The homojunction is able to work as a self-powered device due to the photovoltaic effect, and the ZnO NRs play an important role in the photovoltaic conversion process. Current–voltage (I–V) characteristic shows a turn-on voltage of ∼3V and a rectification ratio of 1.3×102 at 5V. Spectral responsivity exhibits an UV-to-visible rejection ratio of 1×102. The photocurrent rise and decay times are 7 and 45ms, respectively. These results indicate the ZnO:(Ag,N)/ZnO homojunction is an attractive candidate for high-performance self-powered UV photodetectors.

High-performance self-powered UV photodetectors based on TiO2 nano-branched arrays

Nano-branched TiO2 arrays were fabricated on fluorine-doped tin oxide (FTO) glass by a facile two-step chemical synthesis process. Self-powered UV photodetectors based on photoelectrochemical cells (PECs) were assembled using these TiO2 nano-branched arrays as photoanodes. These visible–blind self-powered UV photodetectors exhibit high sensitivity and high-speed photoresponse. Compared with photodetectors based on bare TiO2 nanorod arrays, TiO2 nano-branched arrays show drastically improved photodetecting performance as photoanodes. The photosensitivity increases from 0.03 to 0.22 A W−1 when optimized nano-branched TiO2 arrays are used, corresponding to an incident photon-to-current conversion efficiency higher than 77%. The UV photodetectors also exhibit excellent spectral selectivity and fast response (0.05 s decay time). The improved performance is attributed to a markedly enlarged TiO2/electrolyte contact area and good electron conductivity in the one-dimensional, well-aligned TiO2 nanorod trunk.