Multifunctional interfacial molecular bridge enabled by an aggregation-induced emission strategy for enhancing efficiency and UV stability of perovskite solar cells

The interface defects between the electron transport layer(ETL)and the perovskite layer,as well as the low ultraviolet(UV)light utilization rate of the perovskite absorption layer,pose significant challenges for the commercialization of perovskite solar cells(PSCs).To address this issue,this paper proposes an innovative multifunctional interface modulation strategy by introducing aggregation-induced emission(AIE)molecule 5-[4-[1,2,2-tri[4-(3,5-dicarboxyphenyl)phenyl]ethylene]phenyl]benzene-1,3-dicarboxylic acid(H_(8)ETTB)at the SnO_(2)ETL/perovskite interface.Firstly,the interaction of H_(8)ETTB with the SnO_(2)surface,facilitated by its carboxyl groups,is effective in passivating surface defects caused by noncoord inated Sn and O vacancies.This interaction enhances the conductivity of the SnO_(2)film and adjusts energy levels,leading to enhanced charge carrier transport.Simultaneously,H_(8)ETTB can passivate noncoord inated Pb^(2+)ions at the perovskite interface,promoting perovskite crystallization and reducing the interface energy barrier,resulting in a perovskite film with low defects and high crystalline quality.More importantly,the H_(8)ETTB molecule,can convert UV light into light absorbable by the perovskite,thereby reducing damage caused by UV light and improving the device's utilization of UV.Consequently,the champion PSC based on SnO_(2)-H_(8)ETTB achieves an impressing efficiency of 23.32%and significantly improved photostability compared with the control device after continuous exposure to intense UV radiation.In addition,the Cs_(0.05)(FA_(0.95)MA_(0.05))_(0.95)Pb(I_(0.95)Br_(0.05))_(3)based device can achieve maximum efficiency of 24.01%,demonstrating the effectiveness and universality of this strategy.Overall,this innovative interface bridging strategy effectively tackles interface defects and low UV light utilization in PSCs,presenting a promising approach for achieving highly efficient and stable PSCs.

Laparoscopic gastrectomy for distal gastric cancer

This video presents a standard D2 laparoscopic-assisted gastrectomy for distal gastric cancer. The lymph node dissection of each station is performed as required in the standardized procedure of distal gastrectomy, followed by the Billroth II anastomosis through a small incision.

Multicolor emission from lanthanide ions doped lead-free Cs_(3)Sb_(2)Cl_(9) perovskite nanocrystals

The toxicity of lead ions has become the severe challenge for the all-inorganic lead halide p erovskite materials,although some works have rep orted the lead-free perovskite nanocrystals(NCs),the photoluminescence quantum yield(PLQY)of these materials is still unsatisfactory.Meanwhile,because the halogen ions can be easily exchanged,the controllable multicolor emission in perovskite NCs is difficult to realize in current reports.In this work,we introduced lanthanide ions into lead-free Cs_(3)Sb_(2)Cl_(9) perovskite NCs.Benefitting from the energy transfer between Cs_(3)Sb_(2)Cl_(9) perovskite NC host and lanthanide ions,the multicolor emission was realized.Based on controlling the doping concentration of Tb^(3+)and Eu^(3+)ions,the white light emission under UV excitation would be turned easily in the Tb^(3+)/Eu^(3+)codoped NCs.In addition,efficient energy transfer from perovskite NCs to Tb^(3+)or Eu^(3+)ions is beneficial to improving the optical properties of lead-free perovskite NCs,resulting in maximum PLQYs of red,green and white light emission of 22.6%,19.7%and 28.5%,respectively.Finally,a white light emitting device(WLED)was fabricated with a power efficiency of 18.5 lm/W,which presents the Commission Internationale de l'Eclairage(CIE)of(0.33,0.35).

Enhancing the Efficiency and Durability of Perovskite Solar Cells by Donor-Acceptor Covalent Organic Framework with Thiazolo[5,4-d]thiazole Unit

Donor-Acceptor(D-A)alignment is considered a productive strategy to improve the charge separation efficiency of covalent organic frameworks(COFs)and enhance the charge-transfer yield(CTY)of COFs.Moreover,organic molecules containing heteroatoms can produce coordination interaction with PbI2 of perovskite precursor to affect the crystallization process,thereby impeding the decomposition and improving the stability of perovskite materials.Herein,a thiazolo[5,4-d]thiazole(TZ)-based D-A type COFTPDA-TZDA was designed and synthesized from N,N,N′,N′-tetrakis(4-aminophenyl)-1,4-benzenediamine(TPDA)and 4,4′-(thiazolo[5,4-d]thiazole-2,5-diyl)dibenzaldehyde(TZDA).Upon incorporation into the FAPbI3 layer,COFTPDA-TZDA not only restrained the perovskite defects and enhanced the grain size of perovskite films through the coordination effect of the N atoms of TZDA but also ameliorated the charge transport within the perovskite film,which was the benefit of the D-A structure of COFTPDA-TZDA.As a result,incorporation of COFTPDA-TZDA into the perovskite solar cells(PSCs)led to a remarkable power conversion efficiency(PCE)of up to 23.51%.Furthermore,even after being stored in high relative humidity(RH≈60%)for 480 h,these PSCs maintained over 90.55%of their original PCE.This work sets the foundation for the development of highly efficient and stable PSCs by utilizing TZ-based D-A type COFs.

A novel approach for designing efficient broadband photodetectors expanding from deep ultraviolet to near infrared

Broadband photodetection(PD)covering the deep ultraviolet to near-infrared(200–1000 nm)range is significant and desirable for various optoelectronic designs.Herein,we employ ultraviolet(UV)luminescent concentrators(LC),iodinebased perovskite quantum dots(PQDs),and organic bulk heterojunction(BHJ)as the UV,visible,and near-infrared(NIR)photosensitive layers,respectively,to construct a broadband heterojunction PD.Firstly,experimental and theoretical results reveal that optoelectronic properties and stability of CsPbI3 PQDs are significantly improved through Er3+doping,owing to the reduced defect density,improved charge mobility,increased formation energy,tolerance factor,etc.The narrow bandgap of CsPbI3:Er3+PQDs serves as a visible photosensitive layer of PD.Secondly,considering the matchable energy bandgap,the BHJ(BTP-4Cl:PBDB-TF)is selected as to NIR absorption layer to fabricate the hybrid structure with CsPbI3:Er3+PQDs.Thirdly,UV LC converts the UV light(200–400 nm)to visible light(400–700 nm),which is further absorbed by CsPbI3:Er3+PQDs.In contrast with other perovskites PDs and commercial Si PDs,our PD presents a relatively wide response range and high detectivity especially in UV and NIR regions(two orders of magnitude increase that of commercial Si PDs).Furthermore,the PD also demonstrates significantly enhanced air-and UV-stability,and the photocurrent of the device maintains 81.5%of the original one after 5000 cycles.This work highlights a new attempt for designing broadband PDs,which has application potential in optoelectronic devices.

Flexible double narrowband near-infrared photodetector based on PMMA/core-shell upconversion nanoparticle composites

Flexible narrowband near infrared(NIR)photodetectors(PDs)are urgently in demand in the fastdeveloping era of flexible electronics,due to their crucial roles in various innovative applications.Hence,we designed and synthesized the core-shell structured NaYF4:Yb^(3+),Er^(3+)@NaYF4:Nd^(3+)upconversion nanoparticles(UCNPs),which can be pumped by the 808 and 980 nm lights.The upconversion luminescence(UCL)are significantly enhanced after being assembled with the opal photonic crystals(OPCs)due to the photonic crystal effect,with 55 and 48 folds of enhancement factors under illuminations of 808 and 980 nm lights,respectively.Based on this hybrid,the flexible narrowband PDs were successfully fabricated on the PET substrate with the structure of OPCs/NaYF4:Yb^(3+),Er^(3+)@Nd^(3+)/MAPbl3,which displays excellent detection performance to double narrowband NIR light(808 and 980 nm)benefiting from the amplified UCL,with responsivity of 8.79 and 7.39 A/W,detectivity of 3.01×10^(11)and2.68×10^(11)cm·Hz^(1/2)/W for 808 and 980 nm lights detection respectively,along with short response time in the range of 120-160 ms.Furthermore,the OPCs/NaYF4:Yb^(3+),Er^(3+)@NaYF4:Nd^(3+)/MAPbI3 double narrowband PDs display low photodetection power threshold(0.05 W/cm2),outstanding flexibility,prominent moisture resistance,and good long-time stability.This work displays a new concept of narrowband NIR PDs,which open a new field for specific NIR light detections.

Efficient single-component white light emitting diodes enabled by lanthanide ions doped lead halide perovskites via controlling Forster energy transfer and specific defect clearance

Currently,a major challenge for metal-halide perovskite light emitting diodes(LEDs)is to achieve stable and efficient white light emission due to halide ion segregation.Herein,we report a promising method to fabricate white perovskite LEDs using lanthanide(Ln^(3+))ions doped CsPbCl_(3) perovskite nanocrystals(PeNCs).First,K^(+)ions are doped into the lattice to tune the perovskite bandgap by partially substituting Cs^(+)ions,which are well matched to the transition energy of some Ln^(3+)ions from the ground state to the excited state,thereby greatly improving the Förster energy transfer efficiency from excitons to Ln3+ions.Then,creatine phosphate(CP),a phospholipid widely found in organisms,serves as a tightly binding surface-capping multi-functional ligand which regulates the film formation and enhances the optical and electrical properties of PeNC film.Consequently,the Eu^(3+)doped PeNCs based-white LEDs show a peak luminance of 1678 cd m^(-2) and a maximum external quantum efficiency(EQE)of 5.4%,demonstrating excellent performance among existing white PeNC LEDs from a single chip.Furthermore,the method of bandgap modulation and the defect passivation were generalized to other Ln^(3+)ions doped perovskite LEDs and successfully obtained improved electroluminescence(EL).This work demonstrates the comprehensive and universal strategies in the realization of highly efficient and stable white LEDs via single-component Ln^(3+)ions doped PeNCs,which provides an optimal solution for the development of low-cost and simple white perovskite LEDs.

320-fold luminescence enhancement of [Ru(dpp)3]Cl2 dispersed on PMMA opal photonic crystals and highly improved oxygen sensing performance

Ru complexes([Ru(dpp)3]Cl2)were spin coated on poly(methyl methacrylate)(PMMA)opal photonic crystals(PhCs),and a,320-fold luminescence enhancement was observed compared to that on glass,which is the largest luminescence enhancement of dye molecules by the modulation of three-dimensional(3D)PhCs reported until now.The enhancement mechanism was carefully examined and it was shown that the luminescence of[Ru(dpp)3]Cl2 depended on the molecule concentration and temperature.It can be concluded that the suppressed non-radiative relaxation among the molecules and the field enhancement both contribute significantly to the luminescence enhancement.The PMMA PhC/Ru complex composites were then tested for their intracellular oxygen sensing and cell imaging properties;these composites effectively improved the limit of detection(LOD)and the brightness of the cell images.

Eu^(3+)-Bi^(3+)Codoping Double Perovskites for Single-Component White-Light-Emitting Diodes

Double perovskites(DPs)with Cs_(2)AgInCl_(6) composition,as one of the lead-free perovskites,have been in the spotlight owing to their intriguing optical properties,namely,self-trapped exciton(STE)emission and dopant-induced photoluminescence.However,the current DPs still face the challenge of low photoluminescence efficiency and cannot be applied in practice.Herein,we synthesize the Bi^(3+)and Eu^(3+)codoped Cs_(2)AgInCl_(6) DPs,which displays enhanced STE and Eu^(3+)ions characteristic emissions.Our results indicate that the Eu^(3+)ions mainly substitute the In sites and can increase the radiative recombination rate and exciton binding energy of STEs,which is discovered that Eu^(3+)ions can promote the localization of STEs by breaking the inversion symmetry of the Cs_(2)AgInCl_(6) lattice.The existence of Bi^(3+)ions decreases the excitation(absorption)energy,provides a new absorption channel,and increases the energy transfer rate to Eu^(3+)ions.Through adjusting the Bi^(3+)and Eu^(3+)concentrations,a maximum photoluminescence quantum yield of 80.1%is obtained in 6%Eu^(3+)and 0.5%Bi^(3+)codoped Cs_(2)AgInCl_(6) DPs.Finally,the high-quality single-component white-light-emitting diodes based on Bi^(3+)and Eu^(3+)codoped Cs_(2)AgInCl_(6) DPs and a 410-nm commercial ultraviolet chip are fabricated with the optimum color rendering index of 89,the optimal luminous efficiency of 88.1 lm/W,and a half-lifetime of 1,493 h.This work puts forward an effective lanthanide and transition metals codoping strategy to design single-component white-light emitter,taking a big step forward for the application lead-free DPs.