Application of Bifacial Semitransparent CuInSe2 Absorber to the Bottom Cell in Bifacial Semitransparent Perovskite/CuInSe2 Tandem Solar Cell for Albedo Environment.

Although various types of bifacial solar cells exist, few studies have been conducted on bifacial semitransparent CuInSe2 solar cells (BS-CISe SCs) despite the attractive potential in power generation from both sides in an albedo environment. The optimized BS-CISe SCs with 300 and 800 nm-thick absorber via a streamlined single-stage co-evaporation process exhibit a power conversion efficiency (PCE) of 6.32% and 10.6%, respectively. When double-sided total 2.0 sun illumination is assumed in an albedo environment, the bifacial power generation densities (BPGD) of them increases to 9.41% and 13.9%. Four-terminal bifacial semitransparent tandem solar cells (4T-BST SCs) are fabricated to increase the BPGD by mechanically stacking a BS-perovskite (PVK) top cell on top of a BS-CISe bottom cell with the 300 and 800 nm-thick absorber layers. When summed up, the best top and bottom cell PCEs of the 4T-BST SC with 300 and 800 nm-thick BS-CISe SC are 18.8% and 21.1%, respectively. However, the practical BPGD values of the 4T-BST SC under total 2 sun illumination are interestingly 23.4% and 24.4%, respectively. This is because the BS-CISe bottom cell's thickness affects how much rear-side illumination is transmitted to the BS-PVK top cell, increasing its current density and BPGD.

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.

Darkening of the Greenland Ice Sheet: Fungal Abundance and Diversity Are Associated With Algal Bloom.

Recent studies have highlighted the importance of ice-algal blooms in driving darkening and therefore surface melt of the Greenland Ice Sheet (GrIS). However, the contribution of fungal and bacterial communities to this microbially driven albedo reduction remains unconstrained. To address this significant knowledge gap, fungi were isolated from key GrIS surface habitats (surface ice containing varying abundance of ice algae, supraglacial water, cryoconite holes, and snow), and a combination of cultivation and sequencing methods utilized to characterize the algal-associated fungal and bacterial diversity and abundance. Six hundred and ninety-seven taxa of fungi were obtained by amplicon sequencing and more than 200 fungal cultures belonging to 46 different species were isolated through cultivation approaches. Basidiomycota dominated in surface ice and water samples, and Ascomycota in snow samples. Amplicon sequencing revealed that bacteria were characterized by a higher diversity (883 taxa detected). Results from cultivation as well as ergosterol analyses suggested that surface ice dominated by ice algae and cryoconite holes supported the highest fungal biomass (104-105 CFU/100 ml) and that many fungal taxa recognized as endophytes and plant pathogens were associated with dark ice characterized by a high abundance of ice algae. This paper significantly advances this field of research by investigating for the first time the fungal abundance and diversity associated with algal blooms causing the darkening of the GrIS. There is a strong association between the abundance and diversity of fungal species and the blooming of algae on the surface ice of the Greenland Ice Sheet.