Crystallization Regulation and Morphological Evolution for HTM-free Tin-Lead (1.28eV) Alloyed Perovskite Solar Cells

There have been huge achievements of all-perovskite tandem solar cells,which recently realized the highest power conversion efficiency of 24.8%.However,the complex device structure and complicated manufacture processes severely restrict the further development of all-perovskite tandem solar cells.In this work,we successfully fabricated high-efficiency hole transport material-free(HTM-free)Sn−Pb alloyed narrow bandgap perovskite solar cells(PSCs)by introducing guanidinium thiocyanate(GASCN)and hydroiodic acid(HI)into the perovskite precursor solution.GASCN and HI play a positive synergy effect during perovskite crystallization process resulting in larger grain size,fewer surface defects,and lower trap density to suppress the Sn^(2+)oxidation degradation.Furthermore,they could effectively adjust the energy level of perovskite materials,reduce the energy level difference between perovskite and ITO resulting in more efficiently transport of free hole charge carriers.As a result,with adding GASCN and HI,the achieved highest power conversion efficiency of HTM-free devices increased from 12.58%to 17.85%,which is one of the highest PCEs among all values reported to date for the HTM-free narrow-bandgap(1.2-1.4 eV)Sn−Pb binary PSCs.Moreover,the optimized device shows improved environmental stability.Our additive strategy manifests a remarkable step towards the facile,cost-efficient fabrication of HTM-free perovskite-based tandem solar cells with both high efficiency and simple fabrication process.

Folded technique of self-adherent wrap improves clinical outcomes for wounds after orbital tumour extirpation:a single-center,prospective randomized controlled trial

Background:Using a randomized controlled trial(RCT),to assess the efficacy of the folded technique of self-adherent wrap to eyes after orbital tumour extirpation and compare it with the classic technique.Methods:A single-centre,prospective,randomized,controlled study was conducted among 128 patients who underwent orbital tumour extirpation in this study.The folded and classic techniques of applying self-adherent wraps were randomly allocated to patients(1:1).The primary endpoint was the interface pressure on the affected eye.Secondary efficacy endpoints were the interface pressure above and below the ear of the affected side,above the ear of the non-affected side,and discomfort scores.Postoperative complications were observed for 24 hours.Results:The interface pressure with the folded technique on the affected eye was neither inferior nor superior to the classic technique(1.33±0.07 vs.1.41±0.09 mmHg,P=0.480).Most importantly,the pressure at three other points outside of the affected eye,including above and below the ear of the affected side,and above the ear of the non-affected side,were significantly higher when using the classic technique than when using the folded technique(P=0.041,0.019,and 0.047,respectively).Discomfort scores were higher in the classic technique group than in the folded technique group(2.93±0.30 vs.1.52±0.19,P≤0.001).Conclusions:Findings demonstrated the advantages of using folded technique to apply self-adherent wrap for wounds after orbital tumour extirpation with lower interface pressure outside of the affected eye and patient discomfort scores,without influencing pressure on the affected eye comparing with the classic technique.