• Energy Research

We develop a new series of ionic liquids with dual functionality as a dopant for hole transport materials and a passivator for perovskite surfaces, which enables the production of large-area solar modules with efficiencies approaching 20%.

AbstractTin‐halide perovskite solar cells (THPSCs), while offering low toxicity and high theoretical power conversion efficiency, suffer from inferior device performance compared to lead‐based counterparts. The primary limitations arise from challenges in fabricating high‐quality perovskite films and mitigating the oxidation of Sn2+ ions, which leads to severe non‐radiative voltage losses. To address these issues, we incorporate the rare‐earth element erbium chloride (ErCl3) into PEA0.15FA0.70EA0.15SnI2.70Br0.30 perovskite to effectively control the nucleation and crystal growth, significantly influencing the morphology of the perovskite films. As a result, the ErCl3‐processed THPSC exhibits an impressive open‐circuit voltage (VOC) of 0.83 V and power conversion efficiency (PCE) of 14.0% with the superior light and air stability, compared to the control device (VOC = 0.77 V and PCE = 12.8%). This ErCl3‐strategy provides a feasible solution for high‐performance THPSCs by regulating nucleation/crystallization kinetics and mitigating excessive crystal defects during the preparation process of lead‐free perovskites.image

The utilization of solar energy into electrochemical reduction systems has received considerable attention. Most of these attempts have been conducted in a single electrolyte without a membrane. Here, we report the system combined by the electrochemical CO2 reduction on the Au dendrite electrode and the water oxidation on the Co-Pi electrode with a Nafion membrane. An efficient reduction of CO2 to CO in the cathode using the proton from water oxidation in the anode is conducted using perovskite solar cells under 1 sun condition. The sustainable reaction condition is secured by balancing each reaction rate based on products analysis. Through this system, we collect reduction products such as CO and H2 and oxidation product, O2, separately. Employing separation of each electrode system and series-connected perovskite solar cells, we achieve 8% of solar to fuel efficiency with 85% of CO selectivity under 1 sun illumination.

AbstractIn perovskite solar cells (PSCs), expensive gold or silver metal has traditionally been utilized as the rear electrode for highly efficient performance. In this context, carbon nanotube (CNT) electrodes have been considered promising rear electrodes because of their excellent electrical conductivity, mechanical strength, and chemical stability in PSCs. Despite these favorable characteristics, concerns have been raised about the power conversion efficiency (PCE) and stability of PSCs based on CNTs due to the porosity of CNT electrodes. In this study, we employed both poly(triarylamine) (PTAA) infiltration and rear electrode hidden encapsulation approaches to address issues related to the porosity of thin‐walled carbon nanotube (TWCNT) electrodes to achieve high efficiency and stability. The infiltration of low‐molecular‐weight PTAA into the TWCNT electrode reduced electrode porosity while simultaneously improving the interfacial contact of the TWCNT layer with the perovskite layer. Furthermore, a novel encapsulation design was employed to prevent air and water exposure of the TWCNT electrode, which significantly enhanced device stability. PSCs with TWCNT rear electrodes developed on the basis of these strategies have the best PCE of 19.5% and show long‐term stability, retaining 96% and 74% of the initial PCE after 225 h at maximum power point tracking under AM 1.5G illumination and 916 h at 85°C/85% relative humidity, respectively.image

The defect density on the top surface of the perovskite thin film was significantly higher than that in the bulk. A trimming solvent treatment removed the defective top surface, substantially reducing the defect concentration and strain.