Graded multilayer triple cation perovskites for high speed and detectivity self-powered photodetector via scalable spray coating process

Abstract

Rapid advancements in perovskite materials have led to potential applications in various optoelectronic devices, such as solar cells, light-emitting diodes, and photodetectors. Due to good photoelectric properties, perovskite enables low-cost and comparable performance in terms of responsivity, detectivity, and speed to those of the silicon counterpart. In this work, we utilized triple cation perovskite, well known for its high performance, stability, and wide absorption range, which is crucial for broadband photodetector applications. To achieve improved detectivity and faster response time, graded multilayer perovskite absorbers were our focus. Sequential spray deposition, which allows stacked perovskite architecture without disturbing lower perovskite layers, was used to generate single, double, and triple-layer perovskite photodetectors with proper energy band alignment. In this work, we achieved a record on self-powered perovskite photodetector fabricated from a scalable spray process in terms of EQE and responsivity of 65.30% and 0.30 A W-1. The multilayer devices showed faster response speed than those of single-layer perovskite photodetectors with the champion device reaching 70 µs and 88 µs for rising and falling times. The graded band structure and the internal electric field generated from perovskite heterojunction also increase specific detectivity about one magnitude higher in comparison to the single-layer with the champion device achieving 6.82 × 1012 cmHz1/2 W−1.

Improving morphology and optoelectronic properties of ultra-wide bandgap perovskite via Cs tuning for clear solar cell and UV detection applications

“…According to our findings, and in agreement with others, inhomogeneous distribution of Cs may cause the defects in morphology whether doping level is low or high 27 , 64 . However, the roughness in this work is comparatively less compared to previous work 71 . For comparison, morphologies of perovskite films prepared in DMF: DMSO (4:1) annealed at 100 °C for 15 min and morphologies of films prepared in DMSO solvent, annealed at 125 °C for 15 min are shown in Fig.…”

“…Therefore, EQE reflects the relationship between light intensity and generated current. The detail explanations of EQE, R, and D* are carefully stated in our previous report 71 . In Fig.…”

Photoexcitation of perovskite precursor solution to induce high-valent iodoplumbate species for wide bandgap perovskite solar cells with enhanced photocurrent

“…The red lines show XRD patterns of the aged films (after 30 days) compared to those of fresh films (0 day). After the 30 days in storage, the formation of PbI 2 can be seen around 12.7° 32 , observed in all conditions. (see detailed stability testing results of different durations in Fig.…”

“…As shown in Fig. 1 a, the peak positions of the black α-phase perovskite appear at 14.21 (110), 20.13° (200), 24.70 (202), 28.60 (220) 32.05 (312), 40.87 (224), and 43.46 (314) 32 , 33 . We also observe another peak at 11.57 of the non-perovskite yellow δ-phase, as this phase is more stable than the active black α-phase of FAPbI 3 at room temperature 34 .…”

Recent progress in construction methods and applications of perovskite photodetector arrays

“…Photodiodes can work at zero bias voltage due to the built-in electric field that separates the electronhole pairs generated by the perovskite under photoexcitation and transports them to the corresponding electrodes, resulting in selfpowered photodetection. [63][64][65][66] However, since the photocurrent of the photodiode exhibits a nonlinear characteristic with the light intensity under zero bias voltage, 67 it generally works under reverse bias voltage to promote charge collection, which is different from photovoltaic devices. 68,69 Compared to planar photodetectors, photodiodes have low dark currents and faster response speeds, benefiting from the carrier rejection mechanism and short carrier transmission distances, respectively.…”