Performance improvement of organic phototransistors by using polystyrene microspheres

Advanced Optical Materials

Zhang

et al. 2022

Self Cite

Lead halide hybrid perovskites have been intensively explored as light‐harvesting materials owing to their unique optoelectrical characteristics and simple deposition method. However, the toxicity and instability problems are still hindering their further development and applications. Herein, stable lead‐free double perovskite Cs2AgBiBr6 single crystals (SCs) with outstanding photoelectric properties are prepared. When symmetric Au electrodes are used, the resulting photodetectors (PDs) can have broad spectral response, high responsivity of 4.88 A W−1, external quantum efficiency of 1100%, and detectivity of 1.22 × 1013 Jones, respectively. More interestingly, when asymmetric electrodes (Au and Ag) are used, the authors obtain the first reported self‐driven PD based on the lead‐free perovskite SC, to the best of the authors’ knowledge. The device exhibits good photoresponse properties at a bias of 0 V. Both devices hold short response time at µs scale, which are among the best reported lead‐free perovskite PDs. Both devices demonstrate decent stabilities in air without encapsulation. All results demonstrate that Cs2AgBiBr6 SCs have great potential in the application of optoelectronic devices.

“…Besides, D * is another key parameter for investigating the sensitivity of PDs. When dark current is the main factor to generate current noise, D * is evaluated by the following formula: [ 56 ]

\begin{matrix} D^{*} = R \sqrt{\frac{S}{2 e I_{dark}}} \end{matrix}

…”

Section: Resultsmentioning

confidence: 99%

Applications of Lead‐Free Cs₂AgBiBr₆ Single Crystals in Photodetectors and Self‐Powered Photodetectors by Symmetric/Asymmetric Electrodes

Hao

Advanced Optical Materials

Zhang

et al. 2022

Self Cite

“…The specific detectivity ( D *) reflects the detection capability of PDs to weak light. When current noise only comes from dark current, D * can be calculated by the equation [ 17 ]

D * = \frac{R \sqrt{S}}{\sqrt{2 e I_{dark}}}

…”

Section: Resultsmentioning

confidence: 99%

Air‐Stable Self‐Powered Photodetectors Based on Lead‐Free CsBi₃I₁₀/SnO₂ Heterojunction for Weak Light Detection

Hao

Shen

et al. 2021

Adv Funct Materials

Self Cite

Lead halide perovskites (LHPs) have been widely investigated in photodetection applications owing to their intriguing optoelectronic properties. However, the application of LHPs-based photodetectors (PDs) is hindered because of the toxicity of lead and instability in ambient air. Here, an air-stable selfpowered photodetector is designed based on all-inorganic lead-free CsBi 3 I 10 / SnO 2 heterojunction. The device exhibits broad spectral response in both UV and visible light, fast response on µs scale, and decent long-term stability. The device holds a faster response speed (t r /t d = 7.8/8.8 µs), among the best reported self-powered lead-free perovskites photodetectors. More importantly, the device can display obvious photoresponses even under ultra-weak light intensity as low as 10 pW cm -2 , showing better weak-light sensitivity than previously reported lead-free perovskites photodetectors, to the best of our knowledge. Moreover, the device holds good air stability in the 73 days test without encapsulation. These results suggest that CsBi 3 I 10 /SnO 2 -based self-powered PDs with high photodetection capability possess enormous potential in stable and broadband PDs for weak light detection in the future.

“…Phototransistors are widely used in optoelectronic fields, such as photo-sensors, opto-isolators, image sensors, optically controlled phase shifters, optoelectronic switches, high-speed photodetectors and integrated circuits due to their properties of electric control and electric synchronization [1][2][3][4]. As the inorganic phototransistors developed rapidly, recently, the research on organic phototransistors (OPTs) becomes a hot topic [5][6][7] due to their low cost, light weight, and easy fabrication [8].…”

Section: Introductionmentioning

confidence: 99%

Organic single-crystal phototransistor with unique wavelength-detection characteristics

Zhao

et al. 2018

Sci. China Mater.

Organic phototransistors based on high-quality 2,8-dichloro-5,11-dihexyl-indolo[3,2-b]carbazo (CHICZ) single crystals show the highest photoresponsivity of 3×10 3 A W −1 , photosensitivity of 2×10 4 and the detectivity can achieve 8.4×10 14 Jones. We also discovered good linear dependence of log(photosensitivity) versus the wavelength when the devices were illuminated with a series of sameintensity but different-wavelength lights. The organic phototransistors based on CHICZ single crystal have potential applications in wavelength-detection.