Wan-Jung Kim

Thermally unstable nature of hybrid organic–inorganic perovskites has been a major obstacle to fabricating the long-term operational device. A cesium lead halide perovskite has been suggested as an alternative light absorber, due to its superb thermal stability. However, the phase instability and poor performance are hindering the further progress. Here, cesium lead halide perovskite solar cells with enhanced performance and stability are demonstrated via incorporating potassium cations. Based o

본 연구는 인터넷 중독과 부모와의 의사소통 사이의 쌍방(nonrecursive)관계를 밝히는데 그 목적이 있다. 총 3,020명의 중학생과 고등학생을 각각 3번 측정한 종단자료에 자기회귀 교차지연 모형(autoregressive cross-lagged model)을 적용하여 분석한 결과 인터넷 중독이 부모와의 의사소통에 미치는 영향은 유의하지 않은 것으로 나온 반면, 부모와의 의사소통의 인터넷 중독에 대한 영향은 유의한 것으로 나타났다. 또한, 이러한 두 변인간의 관계성에 남녀 성별차이가 있는 지를 알아보기 위해 다집단 분석을 실행한 결과, 남녀 집단간에 차이는 없는 것으로 나타났다.

Recently, polymer–fullerene based bulk heterojunction (BHJ) solar cells, which contain blends of poly({4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5- b ′]dithiophene-2,6-diyl}{3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4- b ]thiophenediyl}) (PTB7) and [6,6]-phenyl-C 71 -butyric acid methyl ester (PC 71 BM), have been widely studied due to exhibiting high power conversion efficiency (PCE) and well-defined nanomorphology. Because of the short exciton diffusion pathway (less than 10 nm) in organic thi

Metallic nanoparticles (NPs) exhibit a localized surface plasmon resonance (LSPR) and act as scattering centers and subwavelength antennas, so metallic NPs can be incorporated into perovskite solar cells (PSCs) to effectively improve the light absorption of light harvesting devices. Here, we have embedded Au nanoparticles (NPs) into the hole transport layer (HTL) of the PSCs to investigate the photovoltaic effect of the PSCs with Au NPs. Interestingly, it was found that Au NPs dispersed spiro-OM

A stepwise four-electron reaction significantly alleviates the thermodynamics reaction barrier for overall water splitting. Regenerated 1D carbon nitride nanowire bundles from tailoring and reassembly of 2D g-C3N4 produce novel physicochemical and optoelectronic properties, which well realize the stepwise four-electron reaction along with a quantum efficiency of 5.2‰ at 420 nm. As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such mat

The p/n junction of MoS₂/N-RGO co-catalysts not only works as the HER and OER electrocatalyst for H₂ and O₂ generation respectively, but also facilitates charge separation by its inner electric field.

Abstract A general methodology is reported to create organic–inorganic hybrid metal halide perovskite films with enlarged and preferred‐orientation grains. Simply pressing polyurethane stamps with hexagonal nanodot arrays on partially dried perovskite intermediate films can cause pressure‐induced perovskite crystallization. This pressure‐induced crystallization allows to prepare highly efficient perovskite solar cells (PSCs) because the preferred‐orientation and enlarged grains with low‐angle gr

A 2H-MoS2 (H=hexagonal) ultrathin nanomesh with high defect generation and large porosity is demonstrated to improving electrochemical performance, including in lithium-ion batteries (LIBs) and the hydrogen evolution reaction (HER), with the aid of a 3D reduced graphene oxide (RGO) scaffold as fast electron and ion channels. The 3D defect-rich MoS2 nanomesh/RGO foam (Dr-MoS2 Nm/RGO) can be easily obtained through a one-pot cobalt acetate/graphene oxide (GO) co-assisted hydrothermal reaction, in

Herein, we report a tailored Ag mesh electrode coated with poly(3,4-ethylenedioxythiophene) (PEDOT) polymer on a flexible polyethylene terephthalate (PET) substrate. The introduction of this highly conductive polymer solves the existing problems of Ag mesh-type transparent conductive electrodes, such as high pitch, roughness, current inhomogeneity, and adhesion problems between the Ag mesh grid and PEDOT polymer or PET substrate, to result in excellent electron spreading from the discrete Ag mes

Although organic-inorganic halide perovskite (OIHP)-based photovoltaics have high photoconversion efficiency (PCE), their poor humidity stability prevents commercialization. To overcome this critical hurdle, focusing on the grain boundary (GB) of OIHPs, which is the main humidity penetration channel, is crucial. Herein, pressure-induced crystallization of OIHP films prepared with controlled mold geometries is demonstrated as a GB-healing technique to obtain high moisture stability. When exposed

A high current density obtained in a limited, nanometer-thick region is important for high efficiency polymer solar cells (PSCs). The conversion of incident photons to charge carriers only occurs in confined active layers; therefore, charge-carrier extraction from the active layer within the device by using solar light has an important impact on the current density and the related to power conversion efficiency. In this study, we observed a surprising result, that is, extracting the charge carri

Even though poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) has been commonly used as a hole extraction layer (HEL) for p-i-n perovskite solar cells (PSCs), the cells’ photovoltaic performance deteriorates because of the low and unstable work functions (WFs) of PEDOT:PSS versus those of a perovskite layer. To overcome this drawback, we synthesized a copolymer (P(SS-co-TFPMA)) ionomer consisting of PSS and tetrafluoropropylmethacrylate (TFPMA) as an alternative to conventional

Polymer solar cells with enhanced initial cell performances and long-term stability were fabricated by performing a simple dry transfer of a hole extraction layer [poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)] onto an indium tin oxide (ITO) substrate. Due to the very flat surface of the polyurethane acrylate/polycarbonate (PUA/PC) film, which was used as a mold and resembled the surface of the original substrate (silicon wafer), the transferred layer had a very smooth surf