Category: Publications

Research Highlights: Understanding Charge Transport in All-Inorganic Halide Perovskite Nanocrystal Thin-Film Field Effect Transistors

  By

Charge transport mechanism in nanocrystal (NC) films is known to be very different from that in the bulk films. The charge transport in halide perovskite-NC films is further complicated due to the ionic nature of perovskites. In this work, we fabricate all-inorganic CsPbBr3 NCs terminated with short ligands into field effect transistors, which provides a facile platform to study the charge transport mechanism systematically.… Read More

Research Highlights: Guanidinium Doping Enabled Low-temperature Fabrication of High-efficiency All-inorganic CsPbI2Br Perovskite Solar Cells

  By


All-inorganic perovskites, such as CsPbI2Br, have attracted increasing attention because of its potentially better thermal stability. However, a high-quality CsPbI2Br perovskite film usually requires a high fabrication temperature (> 200 ºC) and suffers from unwanted phase transition from a photo-active cubic phase to a photo-inactive orthorhombic phase.
In this work, we present a brand-new means to simultaneously stabilize the photo-active cubic phase and lower the fabrication temperature of perovskite solar cells with guanidinium cations (GA) doping.… Read More

Research Highlights: Manipulating the Mixed-Perovskite Crystallization Pathway Unveiled by In Situ GIWAXS

  By

Mixed perovskites have achieved substantial successes in boosting solar cell efficiency, but the complicated perovskite crystal formation pathway remains mysterious. Here, we report for the first time the detailed crystallization process of mixed perovskites (FA0.83MA0.17Pb(I0.83Br0.17)3) during spin-coating by in situ GIWAXS measurements, and three phase formation stages have been identified: I.… Read More

Research Highlights: Ag-Doped Halide Perovskite Nanocrystals for Tunable Band Structure and Efficient Charge Transport

  By

Heterovalent doping of halide perovskite nanocrystals (NCs), offering potential tunability in optical and electrical properties, remains a grand challenge. Here, we report for the first time a controlled doping of monovalent Ag+ into CsPbBr3 NCs via a facile room temperature synthesis method. Our results suggest that Ag+ ions act as substitutional dopants to replace Pb2+ ions in the perovskite NCs, shifting the Fermi level down-towards the valence band and in turn inducing a heavy p-type character.… Read More

Research Highlights: Hidden structure ordering along backbone of fused-ring electron acceptors enhanced by ternary bulk heterojunction

  By

Fused-ring electron acceptors (FREAs), as a family of non-fullerene acceptors, have achieved tremendous success in pushing the power conversion efficiency of organic solar cells. Here, we reported the detailed molecular packing motifs of two extensively studied FREAs – ITIC and ITIC-Th, which is revealed for the first time the long-range structure ordering along the backbone direction originated from favored end group π-π stacking.… Read More

Research Highlights: Fused-Ring Electron Acceptor ITIC-Th: A Novel Stabilizer for Halide Perovskite Precursor Solution

  By

The stability of perovskite solar cells (PSCs) has been greatly improved recently while very few studies focus on the long-term stability of the perovskite precursor solution. We report a novel route to greatly enhance the long-term stability of perovskite precursor solutions by incorporating a non-fullerene small molecule ITIC-Th. We found that the incorporation of ITIC-Th in the perovskite precursor solution can effectively suppress the unwanted yellow non-perovskite phase (δ-phase) commonly formed in the FAPbI3-based perovskite film made from a long-time aged precursor solution and consequently promote the formation of photoactive perovskite phase (α-phase).… Read More

Research Highlights: High efficiency ternary organic solar cell with morphology-compatible polymers

  By

jmca2017Following our previously proposed selection rule for the two polymers capable of comparable loadings, we report in this work a ternary system composed of two morphologically compatible polymers with distinct chemical structures that can achieve a high PCE of 9.0% with a mass ratio of 1 : 1. Besides the expected improvement in short circuit current due to the broadening of the absorption spectrum, the fill factor of the ternary device is improved significantly.… Read More

Research Highlights : Understanding Morphology Compatibility for High-Performance Ternary Organic Solar Cells

  By

tenary cell compatibilityTernary organic solar cells are emerging as a promising strategy to enhance device power conversion efficiency by broadening the range of light absorption via the incorporation of additional light-absorbing components. However, how to find compatible materials that allow comparable loadings of each component remains a challenge. In this article, we focus on studying the donor polymer compatibilities in ternary systems from a morphological point of view.… Read More