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Semi-transparent perovskite solar cells (ST-PSCs) have broad applications in building integrated photovoltaics. However, the stability of ST-PSCs needs to be improved, especially in n-i-p ST-PSCs since the doped 2,2′,7,7′-tetrakis(N,N-di-p-methoxyphenyl-amine)-9,9′-spirobifluorene (Spiro-OMeTAD) is unstable at elevated temperatures and high humidity. In this work, a π-conjugated polymer poly[(2,6-(4,8-bis(5-(2-ethylhexyl)thiophene-2-yl)-benzo[1,2-b:4,5-b′]dithiophene))-alt-(5,5-(1′,3′-di-2-thienyl-5′,7′-bis(2-ethylhexyl)benzo[1′,2′-c:4′,5′-c′]dithiophene-4,8-dione)] (PBDB-T) is selected to form a polymer composite hole transport layer (HTL) with Spiro-OMeTAD. The sulfur atom of the thiophene unit and the carbonyl group of the polymer interact with the undercoordinated Pb2+ at the perovskite surface, which stabilizes the perovskite/HTL interface and passivates the interfacial defects. The incorporation of the polymer also increases the glass transition temperature and the moisture resistance of Spiro-OMeTAD. As a result, we obtain ST-PSCs with a champion efficiency of 13.71% and an average visible light transmittance of 36.04%. Therefore, a high light utilization efficiency of 4.94% can be obtained. Moreover, the encapsulated device can maintain 84% of the initial efficiency after 751 h under continuous one-sun illumination (at 30% relative humidity) at the open circuit and the unencapsulated device can maintain 80% of the initial efficiency after maximum power tracking for more than 1250 h under continuous one-sun illumination. [ABSTRACT FROM AUTHOR]

Abstract: Here, we present the preparation of thermally stable and solvent resistant micro-patterned polymeric films via static breath-figure process and sequent vulcanization, with a commercially available triblock polymer, polystyrene-b-polyisoprene-b-polystyrene (SIS). The vulcanized honeycomb structured SIS films became self-supported and resistant to a wide range of organic solvents and thermally stable up to 350°C for 2h, an increase of more than 300K as compared to the uncross-linked films. This superior robustness could be attributed to the high degree of polyisoprene cross-linking. The versatility of the methodology was demonstrated by applying to another commercially available triblock polymer, polystyrene-b-polybutadiene-b-polystyrene (SBS). Particularly, hydroxy groups were introduced into SBS by hydroboration. The functionalized two-dimensional micro-patterns feasible for site-directed grafting were created by the hydroxyl-containing polymers. In addition, the fixed microporous structures could be replicated to fabricate textured positive PDMS stamps. This simple technique offers new prospects in the field of micro-patterns, soft lithography and templates. [ABSTRACT FROM AUTHOR]

Abstract: In Qiao’s previous report, only star polymers with T g (glass transition temperature) below 48°C were found forming homogeneous honeycomb coatings on the nonplanar substrates. The polymers with high T g are believed not able to duplicate nonplanar substrate due to their brittleness. This article presents a comprehensive study on the construction of macroporous polymeric films on various nonplanar substrates with static breath figure (BF) technique, using linear polymers with high T g. Two kinds of linear polymers with high T g, polystyrene-b-poly(acrylic acid) and polystyrene without polar end groups, are employed to prepare 3-dimensional macroporous films on different nonplanar substrates. Scanning electronic microscopy views on the side wall in addition to views in-plane prove that polymer films with BF array perfectly replicated the surface features of these substrates. The formation processes of macropores on these substrates are analyzed in detail, and it demonstrates that neither molecular topography nor T g of polymers is the critical factor contouring nonplanar substrate. A new hypothesis involving polymer plasticization and conformation during the solvent evaporation is formulated. [Copyright &y& Elsevier]