Antimony Potassium Tartrate Stabilizes Wide-Bandgap Perovskites for Inverted 4-T All-Perovskite Tandem Solar Cells with Efficiencies over 26%

Wide-bandgap(WBG)perovskites have been attracting much attention because of their immense potential as a front light-absorber for tandem solar cells.However,WBG perovskite solar cells(PSCs)generally exhibit undesired large open-circuit voltage(VOC)loss due to light-induced phase segregation and severe non-radiative recombination loss.Herein,antimony potassium tartrate(APTA)is added to perovskite precursor as a multifunctional additive that not only coordinates with unbonded lead but also inhibits the migration of halogen in perovskite,which results in suppressed non-radiative recombination,inhibited phase segregation and better band energy alignment.Therefore,a APTA auxiliary WBG PSC with a champion photoelectric conversion efficiency of 20.35%and less hysteresis is presented.They maintain 80%of their initial efficiencies under 100 mW cm^(-2)white light illumination in nitrogen after 1,000 h.Furthermore,by combining a semi-transparent WBG perovskite front cell with a narrow-bandgap tin–lead PSC,a perovskite/perovskite four-terminal tandem solar cell with an efficiency over 26%is achieved.Our work provides a feasible approach for the fabrication of efficient tandem solar cells.

Manipulating the morphology of CdS/Sb_(2)S_(3) heterojunction using a Mg-doped tin oxide buffer layer for highly efficient solar cells

Antimony sulfide(Sb_(2)S_(3))is an appealing semiconductor as light absorber for solar cells due to its high absorption coefficient,appropriate band gap(~1.7 e V)and abundance of constituent elements.However,power conversion efficiency(PCE)of Sb_(2)S_(3)-based solar cells still lags much behind the theoretically predicted due to the imperfect energy level alignment at the charge transporting layer/Sb_(2)S_(3)interfaces and hence severe charge recombination.Herein,we insert a high-temperature sintered magnesium(Mg)-doped tin oxide(SnO_(2))layer between cadmium sulfide(Cd S)and fuorine doped tin oxide to form a cascaded energy level alignment and thus mitigate interfacial charge recombination.Simultaneously,the inserted Mg-doped Sn O_(2)buffer layer facilitates the growth of the neibouring Cd S film with orientation followed by Sb_(2)S_(3)film with larger grains and fewer pinholes.Consequently,the resultant Sb_(2)S_(3)solar cells with Mg-doped SnO_(2)deliver a champion PCE of 6.31%,22.8%higher than those without a buffer layer.Our work demonstrates that deliberate absorber growth as well as efficient hole blocking upon an appropriate buffer layer is viable in obtaining solution-processed Sb_(2)S_(3)solar cells with high performance.

The role of aromatic residues in controlling the supramolecular chirality of short amphiphilic peptides

Although the relationship between molecular and supramolecular chirality remains elusive,the existing results have demonstrated the vital role of hydrophilic motifs in controlling the supramolecular handedness of peptide nanofibrils compared with hydrophobic ones.However,unlike conventional hydrophobic residues,we speculate that aromatic hydrophobic residues are mostly likely to play a unique role in regulating the supramolecular handedness because theπ–πstacking interactions of their side chains are directional like hydrogen bonding and can direct high levels of self-assembly due to the geometric confining of aromatic rings.To confirm this hypothesis,we here design a series of amphiphilic short peptides,with their hydrophobic motifs being composed of aromatic residues.Their short lengths not only favor their structural stability,synthesis,and sequence variation but also enable us to readily link their molecular and supramolecular structures.Through the combination of experiments and theoretical simulations,we demonstrate that the peptides containing L-form aromatic residues form left-handed nanofibrils while those containing D-form aromatic residues assemble into right-handed ones,irrespective of the chirality of their C-terminal hydrophilic residue.Theoretical calculations revealed that the stacking of aromatic side chains betweenβ-strands directed the twisting direction of theβ-sheets formed,with L-and D-form phenylalanine side chains stacking in a clockwise and anti-clockwise way,and more ordered and stronger aromatic stacking for homochiral peptides facilitated the formation of nanofibrils with a marked tubular feature.This study has bridged the knowledge gap in our understanding of how aromatic residues affect the supramolecular chirality of short peptides.