Practical Enhancements in Current Density and Power Generation of Bifacial Semitransparent Ultrathin CIGSe Solar Cells via Utilization of Wide Bandgap Zn-Based Buffer.

Among many building-integrated semitransparent photovoltaics (BISTPVs), semitransparent ultrathin (STUT) Cu(Inx ,Ga1-x )Se2 (CIGSe) solar cells are distinguishable due to their potential high power conversion efficiency (PCE) among other thin-film solar cells, versatile applicability based on thin film deposition processes, high stability consisting of all inorganic compositions, and practical expandability to bifacial applications. However, the fundamental trade-off relationship between PCE and transparency limits the performance of BISTPV because implementing a higher semitransparency lowers the optical budget of incoming light. To expand the available optical budget and to enhance the PCE while maintaining a suitable transparency in STUT CIGSe solar cell with single-stage coevaporated 500-nm-thick absorber, an atomic layer deposited wide bandgap Zn(O,S) buffer is introduced as the replacement of conventional CdS buffer, which partially limits incoming light less than 520 nm in wavelength. As a replacement result, more incoming light becomes valid for power conversion, and the short circuit current density (Jsc ) has increased comparatively by 17%, which has directly lead to a large increase in PCE up to 12.41%. Furthermore, Zn(O,S) buffer in the STUT CIGSe solar cell also has enhanced the bifacial compatible efficiency (BCE), which has increased to 14.44% at 1.3 sun and 19.42% at 2.0 sun.

Electrical and Optical Characteristics of Two-Dimensional MoS2 Film Grown by Metal-Organic Chemical Vapor Deposition.

Atomically thin molybdenum disulfide (MoS2) films were synthesized on a SiO2/Si substrate by metal-organic chemical vapor deposition (MOCVD). Raman spectroscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy studies reveal the double-atomic-layer structure and the surface element composition of the MOCVD-grown MoS2 films. The photoluminescence measurement demonstrates a strong emission peak with a bandgap of 685.1 nm, attributed to highly efficient radiative transition at the double atomic layer. The contact resistance between the doubleatomic-layer MoS2 film and metal electrode was measured using the transmission-line modeling method. A Ti/Au electrode forms an ohmic contact with the double-atomic-layer MOCVD-grown MoS2 film, exhibiting a resistivity of 100 kΩ. The field-effect transistor based on the double-atomiclayer MoS2 film exhibits an electron mobility of 1.3×10-4 cm²/V·s and an on/off ratio of 6.5×10² at room temperature.