Study on Performance Improvements in Perovskite-Based Ultraviolet Sensors Prepared Using Toluene Antisolvent and CH3NH3Cl

Abstract

In this study, a simply structured perovskite-based ultraviolet C (UVC) sensor was prepared using a one-step, low-temperature solution-processing coating method. The UVC sensor utilized CH3NH3PbBr3 perovskite as the light-absorbing layer. To improve the characteristics of CH3NH3PbBr3, an antisolvent process using toluene and the addition of CH3NH3Cl were introduced. The device with these modifications exhibited a response rise/fall time of 15.8/16.2 ms, mobility of 158.7 cm2/V·s, responsivity of 4.57 mA/W, detectivity of 1.02 × 1013 Jones, and external quantum efficiency of 22.32% under the 254-nm UV illumination. Therefore, this methodology could be a good approach in facilitating UVC detection.

A Study to Improve the Performance of Mixed Cation–Halide Perovskite-Based UVC Photodetectors

“…Figure 5 b shows the diffusion coefficient ( D ) of the (FAPbI 3 ) 1−x (MAPbBr 3 ) x films (x = 0, 0.03, 0.05, 0.07, and 0.1). D is related to the mobility, as shown in Figure 5 a. Diffusion involves the movement of charge carriers driven by a concentration gradient [ 14 , 43 ]. In the presence of a magnetic field, D is defined using the Einstein relation D = μK T / q , where μ is mobility, K is the Boltzmann constant, T is the temperature of the sample, and q is the amount of charge [ 43 ].…”

“…R is the main parameter that indicates the performance of the photodetector and the response of the device to the irradiated light. R is defined as R = ( I 254 − I dark )/ P × S mA/W [ 14 ], where I 254 is the current when irradiated with 254 nm light, I dark is the dark environment current, P is the power of the incident light, and S is the irradiated area of the device [ 46 ]. R gradually decreased as the bias decreased owing to the change in the photon-charge conversion efficiency of the photodetector [ 10 ].…”

“…However, UVC radiation is emitted by artificial light sources, such as mercury lamps, UV germicidal bulbs, and arc discharges [ 9 , 10 , 11 , 12 ], and is harmful to human health. Additionally, it is the cause of many safety issues in industrial facilities [ 13 , 14 ]. Therefore, it is essential to develop a system to detect UVC radiation in order to increase worker safety and reduce facility management costs.…”

“…Accordingly, photodetectors comprising various materials have been investigated [ 1 ]. Photodetectors comprising materials such as group III–V compound semiconductors, organic polymers, and silicon have been fabricated [ 2 ], and narrow bandgap Si diode sensors equipped with UV filters have been developed [ 14 ]. However, photodetectors containing these materials are expensive and require complex fabrication processes [ 18 ].…”

“…However, photodetectors containing these materials are expensive and require complex fabrication processes [ 18 ]. Additionally, Si diodes offer limited UVC sensitivity because the photogenerated carriers cannot easily reach the depletion layer of the semiconductor [ 14 ].…”