Defects as non-radiative recombination centers hinder the further efficiency improvements of perovskite solar cells(PSCs).Additive engineering has been demonstrated to be an effective method for defect passivation in ...Defects as non-radiative recombination centers hinder the further efficiency improvements of perovskite solar cells(PSCs).Additive engineering has been demonstrated to be an effective method for defect passivation in perovskite films.Here,we employed(4-methoxyphenyl)potassium trifluoroborate(C_(7)H_(7)BF_(3)KO)with and K+functional groups to passivate spray-coated(FAPbI_(3))_(x)(MAPbBr_(3))_(1-x) perovskite and eliminate hysteresis.It is shown that the F of can form hydrogen bonds with the H atom in the amino group of MA+/FA+ions of perovskite,thus reducing the generation of MA+/FA+vacancies and improving device efficiency.Meanwhile,K+and reduced MA+/FA+vacancies can inhibit ion migration,thereby eliminating hysteresis.With the aid of C_(7)H_(7)BF_(3)KO,we obtained hysteresis-free PSCs with the maximum efficiency of 19.5%by spray-coating in air.Our work demonstrates that additive engineering is promising to improve the performance of spray-coated PSCs.展开更多
Ceramic-based dielectric capacitors are becoming more and more important in electronic devices.The ceramics of 0.93K_(0.5)Na_(0.5)NbO_(3)–0.07Bix(Mg_(1/3)Nb_(2/3))O_(3)(0.93KNN–0.07BixMN)(x?0:60,2/3,0.75 and 0.95)we...Ceramic-based dielectric capacitors are becoming more and more important in electronic devices.The ceramics of 0.93K_(0.5)Na_(0.5)NbO_(3)–0.07Bix(Mg_(1/3)Nb_(2/3))O_(3)(0.93KNN–0.07BixMN)(x?0:60,2/3,0.75 and 0.95)were successfully fabricated by virtue of the solid reaction process in this work.The results showed that the amount of Bi content has a significant impact on the ceramics of 0.93KNN–0.07BixMN.XRD indicates that all specimens exhibit a pure perovskite structure and existing oxygen vacancy in the specimens.The mean grain size for all specimens belong to submicron scale,and the sample of x=0.95 owns the smallest grain size is 0.11m.The maximum dielectric constant increases but the phase transition temperature Tm exhibits a contrary tendency at 1MHz with increasing Bi concentration.Besides,all ceramics are relaxor ferroelectric.The impedance analysis further revealed that the activation energy of the ceramics increases with Bi content.Eventually,the highestηof 58.8%and Wrec of 1.30 J/cm^(3) are simultaneously achieved in the sample with x=0.60.Overall,we demonstrate in this work that stoichiometry control of Bi in 0.93KNN–0.07BixMN ceramics is a practical method to obtain the desired structural,dielectric and energy storage properties.展开更多
基金the National Natural Science Foundation of China(51861145101).
文摘Defects as non-radiative recombination centers hinder the further efficiency improvements of perovskite solar cells(PSCs).Additive engineering has been demonstrated to be an effective method for defect passivation in perovskite films.Here,we employed(4-methoxyphenyl)potassium trifluoroborate(C_(7)H_(7)BF_(3)KO)with and K+functional groups to passivate spray-coated(FAPbI_(3))_(x)(MAPbBr_(3))_(1-x) perovskite and eliminate hysteresis.It is shown that the F of can form hydrogen bonds with the H atom in the amino group of MA+/FA+ions of perovskite,thus reducing the generation of MA+/FA+vacancies and improving device efficiency.Meanwhile,K+and reduced MA+/FA+vacancies can inhibit ion migration,thereby eliminating hysteresis.With the aid of C_(7)H_(7)BF_(3)KO,we obtained hysteresis-free PSCs with the maximum efficiency of 19.5%by spray-coating in air.Our work demonstrates that additive engineering is promising to improve the performance of spray-coated PSCs.
基金supported by National Science Foundation of China(Grant Nos.51572163,51577111 and 51607108)the Fundamental Research Funds for the Central Universities(Program Nos.GK201601003,GK201703016,GK201802007,201701011 and 2018CBLZ007).
文摘Ceramic-based dielectric capacitors are becoming more and more important in electronic devices.The ceramics of 0.93K_(0.5)Na_(0.5)NbO_(3)–0.07Bix(Mg_(1/3)Nb_(2/3))O_(3)(0.93KNN–0.07BixMN)(x?0:60,2/3,0.75 and 0.95)were successfully fabricated by virtue of the solid reaction process in this work.The results showed that the amount of Bi content has a significant impact on the ceramics of 0.93KNN–0.07BixMN.XRD indicates that all specimens exhibit a pure perovskite structure and existing oxygen vacancy in the specimens.The mean grain size for all specimens belong to submicron scale,and the sample of x=0.95 owns the smallest grain size is 0.11m.The maximum dielectric constant increases but the phase transition temperature Tm exhibits a contrary tendency at 1MHz with increasing Bi concentration.Besides,all ceramics are relaxor ferroelectric.The impedance analysis further revealed that the activation energy of the ceramics increases with Bi content.Eventually,the highestηof 58.8%and Wrec of 1.30 J/cm^(3) are simultaneously achieved in the sample with x=0.60.Overall,we demonstrate in this work that stoichiometry control of Bi in 0.93KNN–0.07BixMN ceramics is a practical method to obtain the desired structural,dielectric and energy storage properties.
