High-Detectivity Perovskite Light Detectors Printed in Air from Benign Solvents

Abstract

This work reports a straightforward and scalable low-temperature synthesis of methylammonium lead tri-iodide (MAPbI 3 ) perovskite particles. Inks are formulated in benign solvents and are printed in ambient conditions for the fabrication of a light detector with high detectivity. SUMMARYHere, we propose a simple and low-temperature approach for the synthesis of methylammonium lead halide perovskite inks based on sub-micrometer-sized particles with tunable band gap. The particles allow the formulation of inks in benign solvents, such as propan-2-ol, and the printing of the photoactive layers of planar photoconductors with scalable, large-area coating techniques under ambient conditions. When surface traps are passivated with [6,6]-phenyl-C61-butyric acid methyl ester fullerene (PCBM), a high photoconductive gain (exceeding 200 in the blue) and reduced noise produce record-high specific detectivities exceeding 7 3 10 13 cmHz 0.5 /W and gain-bandwidth product values of 7.5 3 10 6 Hz. Given the extreme simplicity of the presented device architecture and the straightforward processing, yielding printable light detectors rivalling established technologies, the present work promises a short-term deployment of printed perovskite detectors in a multitude of opto-electronic applications.

Controlling competing photochemical reactions stabilizes perovskite solar cells

“…he interest in metal halide perovskites has been growing continuously in recent years due to the remarkable evolution of their application in photovoltaics, where power conversion efficiencies exceeding 24% have been achieved 1 , as well as promising performance in light-emitting diodes 2 , photodetectors [3][4][5] and lasers 6,7 . This success owes much to their optimal optoelectronics properties, that is, their high absorption coefficients and long carrier lifetimes [8][9][10] .…”

High‐Sensitivity Flexible X‐Ray Detectors based on Printed Perovskite Inks

“…For the synthesis of MAPbI 3 perovskite particles, we adopted a novel cyclic procedure that we have recently reported in detail. [ 35 ] Briefly, a cyclic approach exploiting only water and propan‐2‐ol as solvents and based on the successive reduction of the size of precursor PbI 2 particles has been used. Since the PbI 2 sheet thickness is directly correlated to the MAPbI 3 crystal's size, [ 36 ] we are able to obtain thinner PbI 2 sheets, which brought us to smaller MAPbI 3 crystals down to few hundreds of nanometers to 1 µm in size with a full conversion from reagents to products.…”

“…The optoelectronic performance of analogous planar devices have been shown to drastically improve, leading to high detectivity devices in the visible range, when a coating of an electron acceptor material, [6,6]‐Phenyl C61 butyric acid methyl ester (PC60BM), is introduced on top of the printed layer. [ 35 ] The PC60BM solution permeates the porous photoactive film, leading to a thin but uniform coverage of the surface of the printed perovskite particles, passivating the traps intrinsically present on the surface of MAPbI 3 (Figure 1b,c). [ 37–40 ]…”

“…It has been demonstrated that the printed perovskite films do not show any measurable XRD peak of PbI 2 even after 4 weeks of storage in air. [ 35 ] Regarding the performance of the devices as X‐ray detectors, we tested their X‐ray response in air with fresh devices (as deposited) and the X‐ray response for aged devices (29 days after deposition). These devices were not encapsulated and kept in ambient conditions.…”

Flat Is Boring in Perovskite Light Detectors

“…7 Moreover, it is not easy to implement the solvents used at the industrial level because of environmental concerns. 8 In this issue of Chem, Caironi and coworkers report 9 a versatile and clean approach that results in a game-changing strategy for achieving highly sensitive photodetectors with MAPI ( Figure 1).…”