Air-Processable Perovskite Solar Cells by Hexamine Molecule Phase Stabilization.

Perovskite solar cells have emerged as a potential energy alternative due to their low cost of fabrication and high power conversion efficiency. Unfortunately, their poor ambient stability has critically limited their industrialization and application in real environmental conditions. Here, we show that by introducing hexamine molecules into the perovskite lattice, we can enhance the photoactive phase stability, enabling high-performance and air-processable perovskite solar cells.

Photoelectrical Dynamics Uplift in Perovskite Solar Cells by Atoms Thick 2D TiS Layer Passivation of TiO Nanograss Electron Transport Layer.

A deficiency in the photoelectrical dynamics at the interface due to the surface traps of the TiO electron transport layer (ETL) has been the critical factor for the inferiority of the power conversion efficiency (PCE) in the perovskite solar cells. Despite its excellent energy level alignment with most perovskite materials, its large density of surface defect as a result of sub lattice vacancies has been the critical hurdle for an efficient photovoltaic process in the device. Here, we report that atoms thick 2D TiS layer grown on the surface of a (001) faceted and single-crystalline TiO nanograss (NG) ETL have effectively passivated the defects, boosting the charge extractability, carrier mobility, external quantum efficiency, and the device stability.

A two-dimensional crystal growth in anatase titania nanostructures driven by trigonal hydronium ions.

Two-dimensional growth or high-energy faceting during a wet-chemical nanocrystal growth involves a dynamic surfactant functionalization that selectively allows a particular crystal plane to grow and simultaneously, passivates others from evolving. Here, by simply controlling the concentration of hydronium ions in a liquid-phase deposition reaction, the two-dimensional growth of a few atoms thick and (001) facet in anatase titania nanostructures can be achieved. The morphology can be modified from nanocube to nanobelt and nanosheet by increasing the hydronium ion concentration.

On the missing links in quantum dot solar cells: a DFT study on fluorophore oxidation and reduction processes in sensitized solar cells.

The possibility of achieving many electrons per absorbed photon of sufficient energy by quantum dots (QDs) drives the motivation to build high performance quantum dot solar cells (QDSCs). Although performance of dye-sensitized solar cells (DSCs), with similar device configuration as that of QDSCs, has significantly improved in the last two decades QDSCs are yet to demonstrate impressive device performances despite the remarkable features of QDs as light harvesters. We investigated the fundamental differences in the optical properties of QDs and dyes using DFT calculations to get insights on the inferior performance of QDSCs.