Synergistic nucleation regulation strategy of 4',4'-Tris(carbazl-9-yl)-triphenylamine and moisture for stably air-processed high performance perovskite photodetectors

Perovskite photodetectors (PPDs) offer a promising solution with low cost and high responsivity, addressing the limitations of traditional inorganic photodetectors. However, there’s still room for improvement in terms of dark current and stability of air-processed PPDs. In this study, 4',4"-Tris(carbazl-9-yl)-triphenylamine (TCTA) is utilized as nucleation agent to enhance the quality of perovskite film. The synergistic effect of TCTA and moisture promotes rapid nucleation of PbI2-PbCl2, resulting in an increased nucleation rate and the elimination of pinholes in the film. By employing additive engineering, we obtain a PbI2-PbCl2 layer with high coverage, leading to a lower density of traps in the corresponding perovskite film. Consequently, the modified PPD exhibits a remarkable reduction in dark current density by over one order of magnitude, reaching 2.4×10-10 A cm-2 at -10 mV, along with a large linear dynamic range (LDR) of 183 dB. Furthermore, the resulting PPD demonstrates remarkable stability, retaining 90% of the initial external quantum efficiency (EQE) value even after continuous operation for over 3200 hours. Due to a fast response time in nanosecond range, the PPD can convert modulated light signals into electrical signals at a speed of 588 Kbit s-1, highlighting great potential in the field of optical communication.