서장원 교수

To fabricate efficient formamidinium tin iodide (FASnI3) perovskite solar cells (PSCs), it is essential to deposit uniform and dense perovskite layers and reduce Sn(4+) content. Here we used solvent-engineering and nonsolvent dripping process with SnF2 as an inhibitor of Sn(4+). However, excess SnF2 induces phase separation on the surface of the perovskite film. In this work, we report the homogeneous dispersion of SnF2 via the formation of the SnF2-pyrazine complex. Consequently, we fabricated

Optimal thickness of a PCBM layer and insertion of the LiF interlayer on a well-controlled flat surface of the perovskite film are essential for fabricating planar perovskite–PCBM solar cells.

A long-standing dream in the large scale application of solar energy conversion is the fabrication of solar cells with high-efficiency and long-term stability at low cost. The realization of such practical goals depends on the architecture, process and key materials because solar cells are typically constructed from multilayer heterostructures of light harvesters, with electron and hole transporting layers as a major component. Recently, inorganic-organic hybrid lead halide perovskites have attr

In this work, we report a peculiar positive solvatochromism in the keto emission of the acceptor-substituted 2-(2'-hydroxyphenyl)benzoxazoles (HBO), which originates from the excited-state intramolecular proton transfer (ESIPT) followed by the intramolecular charge transfer (ICT) and subsequent solvent relaxation. This transient evolution of enhanced ICT characteristic triggered by ESIPT, which is first observed in this work, is responsible for the novel concept of a fast hyperpolarizability mod

Abstract Driven by recent improvements in efficiency and stability of perovskite solar cells (PSCs), upscaling of PSCs has come to be regarded as the next step. Specifically, a high-throughput, low-cost roll-to-roll (R2R) processes would be a breakthrough to realize the commercialization of PSCs, with uniform formation of precursor wet film and complete conversion to perovskite phase via R2R-compatible processes necessary to accomplish this goal. Herein, we demonstrate the pilot-scale, fully R2R

Abstract The energy level alignment of the perovskite and hole transporting materials (HTMs) is essential for increasing the open‐circuit voltage ( V oc ) and enhancing the performance of perovskite solar cells (PSCs). In this work, new sequentially fluorinated poly(triarylamine) polymers (PTAA, 1F‐PTAA, and 2F‐PTAA) with tuned highest occupied molecular orbital (HOMO) energy levels are developed and applied as HTMs into PSCs. The fluorination approach successfully leads to stepwise downshifting

In Sn-based halide perovskite solar cells (PSCs), the oxidation of Sn2+ to Sn4+ under ambient air leads to unwanted p-type doping in the perovskite film, which is a main reason for increased background carrier density and low efficiency. Here, we find that the introduction of bromide into formamidinium tin iodide (CH(NH2)2SnI3, FASnI3) lattice significantly lowers the carrier density of perovskite absorber, which is thought to be a result of reduction of Sn vacancies. It reduces the leakage curr

Abstract The stability of a perovskite solar cell (PSC) is enhanced significantly by applying a customized thin‐film encapsulation (TFE). The TFE is composed of a multilayer stack of organic/inorganic layers deposited by initiated chemical vapor deposition and atomic layer deposition, respectively, whose water vapor transmission rate is on the order of 10 −4 g m −2 d −1 at an accelerated condition of 38 °C and 90% relative humidity (RH). The TFE is optimized, taking into consideration various as

CuPC-applied perovskite solar cells show excellent long-term thermal stability which is attributed to the reliable interface and intrinsic heat-resistance of CuPC.

Porous planar structure, as a new concept of low temperature processing ETL, enables to achieve unprecedented PCE in flexible unit cells and large area modules.

Abstract Recent advances in perovskite solar cells (PSCs) have resulted in greater than 23% efficiency with superior advantages such as flexibility and solution‐processability, allowing PSCs to be fabricated by a high‐throughput and low‐cost roll‐to‐roll (R2R) process. The development of scalable deposition processes is crucial to realize R2R production of flexible PSCs. Gravure printing is a promising candidate with the benefit of direct printing of the desired layer with arbitrary shape and si

A facile approach to make an efficient hybrid bulk heterojunction photovoltaic device with lead sulfide nanocrystals and a low-bandgap polymer is demonstarted, resulting in a power conversion efficiency of about 2–3%.