Regulation of Quantum Wells Width Distribution in Quasi‐2D Perovskite Films for High‐Performance Photodetectors

Abstract

Dynamic optimization of the quantum-well (QW) width distribution in quasi-2D halide perovskite thin films is an effective approach for tuning the properties of photoelectric devices. Here, that the QWs width distribution in quasi-2D perovskite films can be controlled only by using hydroiodic acid (HI) as an additive is demonstrated. A uniform distribution of the colloidal particle size in the quasi-2D perovskite precursor solution is achieved through the formation of soluble iodoplumbate coordination complexes, PbI 3 − from the reaction of HI with PbI 2 , resulting in an improved phase purity in the final film. Density functional theory calculations indicate that the ideal n value quasi-2D perovskite reaction pathway through the PbI 3 − complex has a lower enthalpy of formation than the random nucleation pathway without the HI additive. Benefiting from this merit, a high-quality quasi-2D perovskite film with optimized phase purity delivered a balanced carrier diffusion length and improved carrier mobility. The resultant photodetectors exhibited a light on/off ratio of 50 000, a responsivity of 0.96 A W −1 , and a detectivity of 5.7 × 10 12 Jones at 532 nm. In addition, the state-of-the-art device maintained more than 80% of its initial photocurrent after 720 h of storage at 30% relative humidity.

Two-dimensional complex metal halides: influence of restricted dimensionality on functional properties

“…RP phases have not only demonstrated significant potential in applications such as photovoltaics, LED, and lasing, but also in various other avenues, encompassing photodetection, 136–140 radiation detection, 141–144 scintillation, 145–148 as well as memory applications. 149–152 Despite RP phases generally possessing enhanced stability compared to 3D perovskites due to the incorporation of hydrophobic organic cations, the challenge of stability persists.…”

Annual research review of perovskite solar cells in 2023

“…Despite the superior environmental stabilities of 2D PVKs, the 2D PSCs still exhibited inferior PCE compared to 3D devices because [153] (1) bulky organic spacers produced strong quantum and dielectric confinement effects, inducing a large exciton binding energy and inhibiting the charge carrier transport and (2) 2D PVKs have anisotropic crystallization features, and the bulky insulating organic spacer hinders vertical charge transport between the inorganic PVK sheets. Thus, the design of novel organic spacer cations with large dielectric constant and crystallization kinetics regulation on the crystal plane orientation are two effective strategies for enhancing the performance of 2D PSCs [155,156]. The construction of 2D/3D heterostructures is also an effective strategy to enhance the performance of PSCs; this approach combines the high stability of 2D PVKs and high performance of 3D PVKs [157].…”

Optimization Charge-Carrier Properties of 2D Ruddlesden–Popper Perovskite for Solar Cells

“…When n > 1, organic cations are introduced into the multilayer structure, and the photovoltaic properties of 2DRP perovskite are improved. Currently, the efficiency of 2DRP PSCs ( n ≤ 5) exceeds 19% while exhibiting prominent stability. − Nevertheless, 2DRP perovskites display a significant challenge: high exciton binding energy ( E b ) of several hundred electron volts. This binding energy refers to the energy that holds together electron–hole pairs through electrostatic Coulomb forces.…”