Category: Publications

The tuning of vertical morphology is critical and challenging for organic solar cells (OSCs). In this work, a high open-circuit voltage (VOC) binary D18-Cl/L8-BO system is attained while maintaining the high short-circuit current (JSC) and fill factor (FF) by employing 1,4-diiodobenzene (DIB), a volatile solid additive. It is suggested that DIB can act as a linker between donor or/and acceptor molecules, which significantly modifies the active layer morphology.… Read More

Cesium lead based all-inorganic perovskite solar cells (PSCs) are promising candidates for tandem solar cells owing to their favorable thermal stability and suitable bandgap. However, to exploit the advantage to the full, there is still huge room to reduce energy loss and enhance the V_OC. In this work, low-temperature processed ZnO was developed as an ETL alternative.… Read More

The record power conversion efficiency of organic photovoltaic (OPV) has been boosting rapidly with the development of novel materials and morphology optimization of bulk heterojunction (BHJ) active layer. However, the quantitative determination of out-of-plane nanoscale phase structure of BHJ is still under great challenge. The thin film device structure breaks the symmetry into the in-plane (IP) direction and out-of-plane (OOP) direction with respect to the substrate, leading to an intrinsic anisotropy in the bulk morphology.… Read More

Metal halide perovskites are of fundamental interest in the research of modern thin-film optoelectronic devices, owing to their widely tunable optoelectronic properties and solution processibility. To obtain high-quality perovskite films and ultimately high-performance perovskite devices, it is crucial to understand the film formation mechanisms, which, however, remains a grand challenge, due to the complexity of perovskite composition, dimensionality, and processing conditions.… Read More

Light soaking (LS) has been reported to positively influence the device performance of perovskite solar cells (PSCs), which, however, could be potentially harmful to the loaded devices due to the unstable output. There are very few reports on controls over the LS effect, especially in all-inorganic PSCs. In this work, we present a remarkable LS induced performance enhancement of CsPb(I1-xBrx)3 based PSCs.… Read More

The bulk-heterojunction morphology of organic solar cells is well recognized to be critical to the device performance and has received extensive research efforts in developing viable morphology tuning strategies. In this work, we present a morphology tuning approach for the molecular packing orientation, that is, through the ternary mixing of a donor polymer FTAZ with two distinctly oriented non-fullerene acceptors, IDIC and INIC3.… Read More

Two-step fabricated FAPbI₃-based perovskites have attracted increasing attention because of their excellent film quality and reproducibility. However, the underlying film formation mechanism remains mysterious. In this work, the crystallization kinetics of a benchmark FAPbI₃-based perovskite film with sequential A-site doping of Cs⁺ and GA⁺ has been revealed by in situ X-ray scattering and first-principles calculations.… Read More

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

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

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