Miao Kan

High performance nanoporous silicon photoelectrodes co-catalyzed with an earth abundant [Mo3S13]2− nanocluster via drop coating

Here we report a high performance nanoporous silicon photoelectrode deposited with earth abundant [Mo3S13]2− nanoclusters for hydrogen generation. The earth abundant [Mo3S13]2− nanoclusters with controllable loading can be facilely deposited onto nanoporous Si via drop coating of the monodispersed [Mo3S13]2− suspension followed by drying. The nanoporous Si photoelectrode exhibited a ∼200 mV lower onset potential for photocurrent by reducing the interface resistance for hydrogen generation. The deposition of [Mo3S13]2− also passivates the nanoporous Si with a more stable photocurrent for hydrogen generation than b-Si in a 20 000 s test.

Integration of a functionalized graphene nano-network into a planar perovskite absorber for high-efficiency large-area solar cells

Efficient charge collection is critical in large area (quasi-) planar configuration perovskite solar cells (PSCs) as the cell operation relies on the diffusion of photo-generated charge carriers to charge collector layers. Many defects/traps in the polycrystalline perovskite absorber layer strongly affect the charge collection efficiency because the 2D-like top charge collection layer barely penetrates into the 3D grain boundaries in the perovskite layer to efficiently collect the charge carrier. Inspired by blood capillaries for efficient mass exchange, a charge-collection nano-network for efficient charge collection was incorporated into the perovskite absorber using low-cost, stable amino-functionalized graphene (G-NH2). The integration of such an unprecedented structure enables very efficient charge collection, leading to the significant enhancement of the power conversion efficiency of 1 × 1 cm2 MAPbI3 PSCs from 14.4 to 18.7% with higher reproducibility, smaller hysteresis and enhanced stability. The physicochemical mechanisms underlying the role of this nano charge-collection nano-network in boosting the charge collection in PSCs are elucidated comprehensively, using a combined experimental and theoretical approach, pointing to a new direction towards up-scaling of high-efficiency PSCs.

Bifunctional Stabilization of All-Inorganic α-CsPbI3 Perovskite for 17% Efficiency Photovoltaics

The all-inorganic α-CsPbI3 perovskite with the most suitable band gap faces serious challenges of low phase stability and high moisture sensitivity. We discover that a simple phenyltrimethylammonium bromide (PTABr) post-treatment could achieve a bifunctional stabilization including both gradient Br doping (or alloying) and surface passivation. The PTABr treatment on CsPbI3 only induces less than 5 nm blue shift in UV-vis absorbance but significantly stabilize the perovskite phase with much better stability. Finally, the highly stable PTABr treated CsPbI3 based perovskite solar cells exhibit a reproducible photovoltaic performance with a champion efficiency up to 17.06% and stable output of 16.3%. Therefore, this one-step bifunctional stabilization of perovskite through gradient halide doping and surface organic cation passivation presents a novel and promising strategy to design stable and high performance all-inorganic lead halide.