Prof Henry Snaith FRS

Abstract:

ABSTRACT Reducing non‐radiative charge‐carrier recombination at both p‐ and n‐side interfaces of the perovskite layer is crucial for realizing high‐voltage single‐ and multi‐junction solar cells. Herein, it is demonstrated that co‐depositing a mixture of ethane‐1,2‐diammonium iodide and different oleyl‐based amphiphiles renders a passivator‐insulator modification at the perovskite–C 60 interface, which suppresses n‐side contact losses in narrow‐bandgap (∼1.26 eV) Sn–Pb perovskite solar cells. Interestingly, a cationic oleyl‐based amphiphile introduced concurrently with the poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate hole‐transport‐layer, deposited from an aqueous dispersion in 1‐propanol, also reduces the p‐side energy loss by providing a substrate for high‐quality perovskite films and limiting the contact between the doped hole‐transport‐layer and the perovskite layer atop. This double‐sided interface modification strategy enables open‐circuit voltage ( V oc ) values of up to 0.91 V—over 91% of the detailed‐balance limit—for 22.6% efficient single‐junction Sn–Pb perovskite solar cells. Monolithic all‐perovskite tandem solar cells show V oc and efficiency values of up to 2.16 V and 26.1%, respectively. The results demonstrate that insulating‐passivating interface modifications between the perovskite and charge transport layers represent an effective strategy for reducing energy losses in emerging perovskite solar cell technologies.

Abstract:

The practical application of perovskite nanocrystals has been hindered by their intrinsic instability, arising from the coupled effects of soft ionic lattices, ion migration, and surface reactions. A hierarchical shell strategy now addresses these intertwined degradation pathways through lattice-interface “interlocking”, achieving T90 values exceeding 27,000 h under continuous blue-light exposure. Notably, the resulting hierarchical shell-perovskite nanocrystals enable reliable colour-conversion display prototypes.

Abstract:

Commercialisation of perovskite photovoltaics (PV) hinges on scalable, environmentally responsible manufacturing; a challenge compounded by the widespread use of toxic solvents in current ink formulations. Here, we introduce a significantly reduced toxicity (SRT) solvent system for methylammonium lead iodide (MAPbI3) perovskite inks, specifically engineered for room-temperature, gas blowing assisted bar coating. Our formulation, based on ethanol and 2-methyltetrahydrofuran (2MeTHF) with a minimal fraction of dimethyl sulfoxide (DMSO), enables rapid crystallisation under mild thermal conditions following deposition, ensuring compatibility with both rigid and flexible substrates. This approach delivers uniform, defect-free perovskite films across large areas, validated through multi-scale characterisation techniques. Leveraging this SRT ink, we fabricate monolithically interconnected mini-modules (active area: 11.5cm²) using a laser-based P1–P4 scribing process, achieving power conversion efficiencies (PCEs) exceeding 18%, among the highest reported for green, scalable perovskite processing. Performance gains are further enhanced by integrating bar-coated self-assembled monolayers (SAMs) as hole transport layers (HTLs), demonstrating industrial viability without compromising efficiency. Beyond device metrics, this work establishes a new sustainability benchmark by eliminating hazardous solvents and aligning with green chemistry principles, including low toxicity, biodegradability, and reduced environmental persistence. Our findings represent a critical step toward high-throughput, eco-friendly fabrication of perovskite solar modules, bridging the gap between laboratory innovation and industrial deployment.

Abstract:

We investigate the impact of employing fullerene self-assembled monolayers (SAMs) in conjunction with SnO2 electron-transport layers (ETLs) in negative–intrinsic–positive (n–i–p) perovskite solar cells. We compare the efficacy of the fullerene-SAM surface-binding group—carboxylic or phosphonic acid—on the passivation, charge transport, and energetics of the modified-SnO2 surface. Planar n–i–p perovskite solar cells with these SAM-modified SnO2 exhibit significantly reduced hysteresis, and the steady-state maximum power point tracked efficiencies (η MPP) of the devices improved from an average of 18.6–20.0% comparing devices with neat SnO2 to the C60-PA SAM inclusion, respectively. While C60-PA SAM improved the initial solar cell efficiency, this benefit was not maintained during light exposure at elevated temperatures as the fullerene SAM weakened adhesion at the perovskite/metal oxide interface in the aged devices. These results highlight the importance of improving the mechanical robustness of perovskite/charge-transport layer interfaces under operational aging conditions.

Abstract:

ABSTRACT The development of stable and spectrally pure green emitters remains a critical challenge for high performance full color displays and solid‐state lighting. In this work, we present a simple and effective approach to fabricate perovskite light‐emitting diodes based on CsPbBr 3 quantum dots confined within a nanoporous silica scaffold. The introduction of linear (n) or branched (t) butylammonium bromide and crown ethers into the precursor solution prior to infiltration induces improved charge injection and transport across the active layer. This dual‐additive approach contributes to a dramatic enhancement in device performance, leading to a highest luminance exceeding 10,000 cd m − 2 , and markedly improved operational stability. The optimized devices exhibit ultrapure green emission centered at 520 nm with a narrow spectral width below 20 nm. The proposed method provides a versatile and scalable route toward bright, spectrally pure, and durable perovskite light‐emitting devices.