Peng Qin

Inorganic hole conductor-based lead halide perovskite solar cells with 12.4% conversion efficiency

Organo-lead halide perovskites have attracted much attention for solar cell applications due to their unique optical and electrical properties. With either low-temperature solution processing or vacuum evaporation, the overall conversion efficiencies of perovskite solar cells with organic hole-transporting material were quickly improved to over 15% during the last 2 years. However, the organic hole-transporting materials used are normally quite expensive due to complicated synthetic procedure or high-purity requirement. Here, we demonstrate the application of an effective and cheap inorganic p-type hole-transporting material, copper thiocyanate, on lead halide perovskite-based devices. With low-temperature solution-process deposition method, a power conversion efficiency of 12.4% was achieved under full sun illumination. This work represents a well-defined cell configuration with optimized perovskite morphology by two times of lead iodide deposition, and opens the door for integration of a class of abundant and inexpensive material for photovoltaic application.

Perovskite Solar Cells with 12.8% Efficiency by Using Conjugated Quinolizino Acridine Based Hole Transporting Material

A low band gap quinolizino acridine based molecule was designed and synthesized as new hole transporting material for organic-inorganic hybrid lead halide perovskite solar cells. The functionalized quinolizino acridine compound showed an effective hole mobility in the same range of the state-of-the-art spiro-MeOTAD and an appropriate oxidation potential of 5.23 eV vs the vacuum level. The device based on this new hole transporting material achieved high power conversion efficiency of 12.8% under the illumination of 98.8 mW cm(-2), which was better than the well-known spiro-MeOTAD under the same conditions. Moreover, this molecule could work alone without any additives, thus making it to be a promising candidate for solid-state photovoltaic application.

Low band gap S,N-heteroacene-based oligothiophenes as hole-transporting and light absorbing materials for efficient perovskite-based solar cells

Novel low band gap oligothiophenes incorporating S,N-heteropentacene central units were developed and used as hole-transport materials (HTMs) in solid-state perovskite-based solar cells. In addition to appropriate electronic energy levels, these materials show high photo-absorptivity in the low energy region, and thus can contribute to the light harvesting of the solar spectrum. Solution-processed CH3NH3PbI3-based devices using these HTMs achieved power conversion efficiencies of 9.5–10.5% in comparison with 7.6% obtained by reference devices without HTMs. Photoinduced absorption spectroscopy gave further insight into the charge transfer behavior between photoexcited perovskites and the HTMs.

Stable and Efficient Perovskite Solar Cells Based on Titania Nanotube Arrays

Highly ordered 1D TiO2 nanotube arrays are fabricated and applied as nanocontainers and electron transporting material in CH3 NH3 PbI3 perovskite solar cells. The optimized device shows a power conversion efficiency of 14.8%, and improved stability under an illumination of 100 mW cm(-2). This is the best result based on 1D TiO2 nanostructures so far.

A hybrid lead iodide perovskite and lead sulfide QD heterojunction solar cell to obtain a panchromatic response

We report for the first time on co-sensitization between CH3NH3PbI3 perovskite and PbS quantum dots (QDs) in a heterojunction solar cell to obtain a panchromatic response from the visible to near IR regions. Following the deposition of the sensitizers on a TiO2 film, an Au thin layer is evaporated on top as a back contact. Importantly, the CH3NH3PbI3 nanoparticles and the PbS QDs used here simultaneously play both the role of a light harvester and a hole conductor, rendering superfluous the use of an additional hole transporting material. The mesoscopic CH3NH3PbI3 (perovskite)–PbS (QD)/TiO2 heterojunction solar cell shows an impressive short circuit photocurrent (Jsc) of 24.63 mA cm−2, much higher than those of the individual CH3NH3PbI3 perovskite and the PbS QD solar cells. The advent of such co-sensitization mesoscopic heterojunction solar cells paves the way to extend the absorbance region of the promising low cost, high-efficiency perovskite based solar cells.

Dopant-Free Hole-Transporting Materials for Stable and Efficient Perovskite Solar Cells

Molecularly engineered novel dopant-free hole-transporting materials for perovskite solar cells (PSCs) combined with mixed-perovskite (FAPbI3 )0.85 (MAPbBr3 )0.15 (MA: CH3 NH3+ , FA: NH=CHNH3+ ) that exhibit an excellent power conversion efficiency of 18.9% under AM 1.5 conditions are investigated. The mobilities of FA-CN, and TPA-CN are determined to be 1.2 × 10-4 cm2 V-1 s-1 and 1.1 × 10-4 cm2 V-1 s-1 , respectively. Exceptional stability up to 500 h is measured with the PSC based on FA-CN. Additionally, it is found that the maximum power output collected after 1300 h remained 65% of its initial value. This opens up new avenue for efficient and stable PSCs exploring new materials as alternatives to Spiro-OMeTAD.