Qianqian Lin

Low noise, IR-blind organohalide perovskite photodiodes for visible light detection and imaging.

Solution-processed organohalide perov-skite photodiodes that have performance metrics matching silicon, but are infrared-blind are reported. The perovskite photodiodes operate in the visible band, have low dark current and noise, high specific detectivity, large linear dynamic range, and fast temporal response. Their properties make them promising candidates for imaging applications.

Efficient, monolithic large area organohalide perovskite solar cells

Solar cells based on organohalide perovskites (PSCs) have made rapid progress in recent years and are a promising emerging technology. An important next evolutionary step for PSCs is their up-scaling to commercially relevant dimensions. The main challenges in scaling PSCs to be compatible with current c-Si cells are related to the limited conductivity of the transparent electrode, and the processing of a uniform and defect-free organohalide perovskite layer over large areas. In this work we present a generic and simple approach to realizing efficient solution-processed, monolithic solar cells based on methylammonium lead iodide (CH3NH3PbI3). Our devices have an aperture area of 25 cm2 without relying on an interconnected strip design, therefore reducing the complexity of the fabrication process and enhancing compatibility with the c-Si cell geometry. We utilize simple aluminum grid lines to increase the conductivity of the transparent electrode. These grid lines were exposed to an UV-ozone plasma to grow a thin aluminum oxide layer. This dramatically improves the wetting and film forming of the organohalide perovskite junction on top of the lines, reducing the probability of short circuits between the grid and the top electrode. The best devices employing these modified grids achieved power conversion efficiencies of up to 6.8%.

Room-temperature tilted-target sputtering deposition of highly transparent and low sheet resistance Al doped ZnO electrodes

Target-tilted room temperature sputtering of aluminium doped zinc oxide (AZO) provides transparent conducting electrodes with sheet resistances of <10 Ω □-1 and average transmittance in the visible region of up to 84%. The properties of the AZO electrode are found to be strongly dependent on the target-tilting angle and film thickness. The AZO electrodes showed comparable performance to commercial indium tin oxide (ITO) electrodes in organic photovoltaic (OPV) devices. OPV devices containing a bulk heterojunction active layer comprised of poly(3-n-hexylthiophene) (P3HT):phenyl-C61-butyric acid methyl ester (PCBM) and an AZO transparent conducting electrode had a power conversion efficiency (PCE) of up to 2.5% with those containing ITO giving a PCE of 2.6%. These results demonstrate that AZO films are a good alternative to ITO for transparent conducting electrodes.

A Triarylamine-Based Anode Modifier for Efficient Organohalide Perovskite Solar Cells

Organohalide lead perovskite solar cells have emerged as a promising next-generation thin-film photovoltaic technology. It has been clearly recognized that interfacial engineering plays a critical role in cell performance. It has been also proposed that the open-circuit voltage is dependent on the ionization potential of the hole transport layer at the anode. In this communication, we report a simple modification of the anode with a triarylamine-based small molecule (1), which avoids the need to use standard hole transport materials and delivers a relatively high open-circuit voltage of 1.08 V and a power conversion efficiency of 16.5% in a simple planar architecture.