Prof Yen-Hung Lin

Abstract:

Vacuum-based deposition is a scalable, solvent-free industrial method ideal for uniform coatings on complex substrates. However, all vacuum-deposited perovskite solar cells fabricated by thermal evaporation trail solution-processed counterparts in efficiency and stability due to film quality challenges, necessitating advancement and improved understanding. Here, we report a co-evaporation route for 1.67-eV wide-bandgap perovskites by introducing a PbCl2 co-source to optimize film quality. We promote perovskite formation with pronounced (100) “face-up” orientation and deliver a certified all vacuum-deposited solar cell with 18.35% efficiency (19.3% in the lab) for 0.25-cm2 devices (18.5% for 1-cm2 cells). These cells retain 80% of peak efficiency after 1,080 hours under the ISOS-L-2 protocol. Leveraging operando hyperspectral imaging, we provide spatiotemporal spectral insight into halide segregation and trap-mediated recombination, correlating microscopic luminescence features with macroscopic device performance while distinguishing radiative from non-ideal recombination channels. We further demonstrate 27.2%-efficient 1-cm2 evaporated perovskite-on-silicon tandems and outdoor stability of all vacuum-deposited tandems in Italy, retaining ~80% initial performance after 8 months.

Abstract:

Perovskite solar cells (PSCs) have reached power conversion efficiencies (PCEs) of 28%, but their scalable manufacturing remains hindered by the use of hazardous solvents and inert-atmosphere processing. Green-solvent air-processing is a promising route towards sustainable perovskite photovoltaics, yet its efficiency remains limited by an unresolved chemical bottleneck. Here we report that air-processing disrupts solvent–lead coordination in the precursor state, leading to intermediate-phase heterogeneity, defect formation, and non-uniform crystallization in dimethyl sulfoxide (DMSO)-based systems. We resolve this challenge by introducing a coordination-reconfiguration strategy in a green DMSO/isopropanol (IPA) solvent system using iodo-binaphthyl-sulfonimide (IBS) as a coordination-reconfiguring agent. Ab initio calculations and experimental results indicate that IBS preferentially binds PbI2, weakens the DMSO–PbI2 interaction, and reconfigures the precursor coordination environment, thereby suppressing air-disrupted solvated intermediates and enabling homogeneous crystallization of phase-pure perovskite films. The p–i–n PSCs processed from this system achieve PCEs of 26.51% in N2 and 26.20% in air, outperforming air-processed DMF/DMSO controls, while 13.3 cm² mini-modules deliver 23.20% PCE with strong operational and damp-heat stability.

Abstract:

Crystallographic orientation and lattice strain directly govern performance and stability; however, they are often treated as independent structural parameters, and therefore their combined influence on non-radiative recombination remains poorly understood. Here, we reveal the interplay between these parameters and establish their correlation with non-radiative recombination in perovskite solar cells (PSCs). The coupled control of structural parameters is achieved through novel bimolecular cooperative interactions between sodium hydroxyquinoline sulfonate and sodium aminonaphthalene sulfonate. These interactions regulate crystallization at molecular level by destabilizing solvent–PbI2 adducts. As a result, they promote out-of-plane growth of corner-sharing [PbI6]^4─ networks along [100] direction and shift the lattice strain from a tensile to a compressive state. This leads to an open-circuit voltage of 1.22 V (only 49 mV behind the theoretical limit), achieving a power conversion efficiency (PCE) up to 26.21% and a reverse-bias breakdown voltage of −16.5 V in PSCs. Furthermore, the device retains 90% of its initial PCE after 3300 h at >85% relative humidity. Control experiments further confirm that this integrated structural tuning is the dominant factor governing suppressed non-radiative recombination and enhanced breakdown voltage.

Abstract:

Multivalent, resonance-stabilized amidinium ligands enable stronger chemical coordination and reduced deprotonation compared with conventional monovalent ammonium ligands in low-dimensional perovskites. Here, we introduce a controllable one- to two-dimensional (1D-to-2D) structural transition strategy by systematically tuning ligand conformation, thereby modulating hydrogen bonding, π-π stacking, and basicity to elucidate the relationship between molecular structure, interfacial interactions, and resulting dimensionality. The 1D-amidinium perovskite structure, with its pronounced geometric anisotropy, impedes uniform surface coverage and defect passivation. In contrast, the 2D-amidinium perovskite forms a continuous, homogeneous interfacial layer, enabling more effective defect passivation and favorable energy-level alignment. With dimensionality control, inverted 3D/2D-amidinium perovskite solar cells deliver 25.4% power conversion efficiency (1.1 square centimeters, steady-state certified) and maintain >95% of their initial efficiency after 1100 hours of continuous 1-sun operation at 85°C.

Abstract:

Perovskite solar cells (PSCs) are emerging as a particularly promising technology to enhance the world’s renewable energy generation capacity. As PSCs are transitioning from research to industrial-scale production, there is an important opportunity to establish sustainable manufacturing pathways. Here, we present a closed-loop framework for the development of environmentally sustainable PSCs and highlight strategies to achieve this vision. First, we analyse the sourcing of raw materials and compare two established PSC fabrication techniques, vapour-phase deposition and solution processing, evaluating their respective advantages and limitations in terms of economic feasibility and environmental impact. Second, we examine solution processing methods, focusing on solvent system design for the preparation of high-quality perovskite films and on the use of non-hazardous or less-hazardous solvents. Third, we examine potential lead-release concerns during PSC operation and discuss approaches to minimize associated environmental risks. Fourth, we summarize effective recycling methods for main PSC components to support a circular production model. Finally, we identify key challenges and outline future research directions to achieve fully sustainable, closed-loop PSC technologies.