Snaith group

Abstract:

The use of a small organic molecular passivator is proven to be a successful strategy for producing higher-performing quasi-2D perovskite light-emitting diodes (PeLEDs). The small organic molecule can passivate defects on the grain surround and surface of perovskite crystal structures, preventing nonradiative recombination and charge trapping. In this study, a new small organic additive called 2, 8-dibromodibenzofuran (diBDF) is reported and examines its effectiveness as a passivating agent in high-performance green quasi-2D PeLEDs. The oxygen atom in diBDF, acting as a Lewis base, forms coordination bonds with uncoordinated Pb²⁺, so enhancing the performance of the device. In addition, the inclusion of diBDF in the quasi-2D perovskite results in a decrease in the abundance of low-n phases, hence facilitating efficient carrier mobility. Consequently, PeLED devices with high efficiency are successfully produced, exhibiting an external quantum efficiency of 19.9% at the emission wavelength of 517 nm and a peak current efficiency of 65.0 cd A-¹.

Abstract:

Mixed lead-tin (Pb:Sn) halide perovskites are promising absorbers withnarrow-bandgaps (1.25–1.4 eV) suitable for high-efficiency all-perovskitetandem solar cells. However, solution processing of optimally thick Pb:Snperovskite films is notoriously difficult in comparison with their neat-Pbcounterparts. This is partly due to the rapid crystallization of Sn-basedperovskites, resulting in films that have a high degree of roughness. Rougherfilms are harder to coat conformally with subsequent layers usingsolution-based processing techniques leading to contact between theabsorber and the top metal electrode in completed devices, resulting in a lossof VOC , fill factor, efficiency, and stability. Herein, this study employs anon-continuous layer of alumina nanoparticles distributed on the surface ofrough Pb:Sn perovskite films. Using this approach, the conformality of thesubsequent electron-transport layer, which is only tens of nanometres inthickness is improved. The overall maximum-power-point-tracked efficiencyimproves by 65% and the steady-state VOC improves by 28%. Application ofthe alumina nanoparticles as an interfacial buffer layer also results in highlyreproducible Pb:Sn solar cell devices while simultaneously improving devicestability at 65 °C under full spectrum simulated solar irradiance. Aged devicesshow a six-fold improvement in stability over pristine Pb:Sn devices,increasing their lifetime to 120 h

Abstract:

Here we deposit the data and code necessary to generate the analysis found in our work. We have included: Simulation output from drift diffusion simulations; Photoluminescence imaging data (in a semi-raw and processed format); Outputs from our Bayesian analysis combining the two; and a clone of the code (from our public git repo) used to generate the analysis.

Abstract:

Data and figures generated for the manuscript 'Chloride-based additive engineering for efficient and stable wide-bandgap perovskite solar cells'.

Abstract:

The limited conductivity of existing transparent conducting oxide (TCO) greatly restricts the further performance improvement of perovskite solar cells (PSCs), especially for large-area devices. Herein, buried-metal-grid tin-doped indium oxide (BMG ITO) electrodes are developed to minimize the power loss caused by the undesirable high sheet resistance of TCOs. By burying 140-nm-thick metal grids into ITO using a photolithography technique, the sheet resistance of ITO is reduced from 15.0 to 2.7 Ω sq^-1 . The metal step of BMG over ITO has a huge impact on the charge carrier transport in PSCs. The PSCs using BMG ITO with a low metal step deliver power conversion efficiencies (PCEs) significantly better than that of their counterparts with higher metal steps. Moreover, compared with the pristine ITO-based PSCs, the BMG ITO-based PSCs show a smaller PCE decrease when scaling up the active area of devices. The parallel-connected large-area PSCs with an active area of 102.8 mm² reach a PCE of 22.5%. The BMG ITO electrodes are also compatible with the fabrication of inverted-structure PSCs and organic solar cells. The work demonstrates the great efficacy of improving the conductivity of TCO by BMG and opens up a promising avenue for constructing highly efficient large-area PSCs.