Cyclopentadithiophene(CPDT)-based polymers have emerged as promising research platforms for multi⁃color electrochromic materials due to their favorable color tunability.However,insufficient cyclic stability has hinder...Cyclopentadithiophene(CPDT)-based polymers have emerged as promising research platforms for multi⁃color electrochromic materials due to their favorable color tunability.However,insufficient cyclic stability has hindered their translation into practical applications.In this study,two CPDT-based conjugated polymers with distinct substituent groups were designed and synthesized:PCPDT-Ph(copolymerized with unsubstituted benzene units)and PCPDT-PhOMe(copolymerized with dimethoxy-substituted benzene units).The influence of dimethoxy substitution on the electrochromic properties and stability of the polymers was systematically investigated.Electro⁃chemical and electrochromic characterizations demonstrated that the electron-donating ability of the dimethoxy groups not only effectively regulated the polymer’s intrinsic properties but also significantly enhanced its cycling stability.Compared with PCPDT-Ph,PCPDT-PhOMe exhibited a reduced onset oxidation potential from 0.66 V(vs.Ag/AgCl)to 0.46 V,an upshifted highest occupied molecular orbital(HOMO)energy level,and a narrowed optical band gap(calculated theoretically)from 1.73 eV to 1.61 eV.The PCPDT-PhOMe film showed magenta in the neutral state and transparency in the oxidized state,with a color difference(ΔE*a b)of 46.36.The coloring/bleaching response times were measured as 0.7/0.6 s,and the optical contrast retention reached 84%after 1000 cycles,outperforming the PCPDT-Ph film(79.5%retention after 500 cycles).Additionally,it exhibited a coloration efficiency of 543.9 cm^(2)/C,demonstrating favorable comprehensive electrochromic performance.Electrochromic devices assembled with PCPDT-PhOMe achieved reversible switching between magenta and transparent states,with a response time of≤1.0 s and a contrast retention of 71%after 30000 cycles,indicating good stability.This work clarifies the role of substituent electronic effects in regulating the electrochromic properties of CPDT-based polymers,providing experimental basis and theoretical support for the molecular design of solution-processable thiophene-based electrochromic materials.Furthermore,it validates the potential application of PCPDT-PhOMe in smart windows,electronic displays,and other related fields.展开更多
In this paper, a new D-A copolymer, PFDBCPDT, which consists of benzo-2,1,3-thiadiazole as acceptor units and cyclopentadithiophene and fluorene as donor units, was synthesized. The thermal, electrochemical, photophys...In this paper, a new D-A copolymer, PFDBCPDT, which consists of benzo-2,1,3-thiadiazole as acceptor units and cyclopentadithiophene and fluorene as donor units, was synthesized. The thermal, electrochemical, photophysical and photovoltaic properties of PFDBCPDT were studied. PFDBCPDT showed a low optical band gap of 1.84 eV, and relatively low HOMO level of-5.69 eV. The best device performance was obtained by PFDBCPDT/PC61BM （1：3） with 0.5 vol% DIO. The device exhibited a power conversion efficiency of 3.06%, with a relatively high open circuit voltage of 0.87 eV.展开更多
Main observation and conclusion A series of all-donor type alternating(D1-D2)monodisperse oligomers based on cyclopentadithiophene(CPDT)and 1,4-difluoro-benzene(DFB)with gradually increasing chain lengths containing 3...Main observation and conclusion A series of all-donor type alternating(D1-D2)monodisperse oligomers based on cyclopentadithiophene(CPDT)and 1,4-difluoro-benzene(DFB)with gradually increasing chain lengths containing 3 to 15 monomers were successfully synthesized via one-pot C-H direct arylation reaction.As confirmed by various structural characterizations,all these long-chain oligomers are monodispersed with defined structures.The length-dependent optical and electrochemical properties with the evolution from the shortest oligomer(01)to the longest oligomer(07)and their parent polymer P1 have been studied in details.By simply tuning the mixing ratio of discrete oligomers,the photoluminescence(PL)in a wide range of color emissions extending to near-white can be facilely modulated,ilus-trating the potential of these monodisperse conjugated oligomers for light emission application.The atom-,step-and pot-economic synthetic strategy here developed will open the door toward efficient and controllable synthesis ofπ-conjugated oligomers for accu-rate structure-property relationship study and optic&electronic device applications.展开更多
The rapid synthesis of structurally complicated electron donors&acceptors still remains a major challenge in organic solar cells(OSC).In this work,we developed a highly efficient strategy to access long-chain olig...The rapid synthesis of structurally complicated electron donors&acceptors still remains a major challenge in organic solar cells(OSC).In this work,we developed a highly efficient strategy to access long-chain oligomeric donor and acceptors for OSC applications.A series of cyclopentadithiophene(CPDT)and benzothiadiazole(BT)-basedπ-conjugated oligomers,i.e.,three oligomeric acceptors(BTDT)n-IC(n=1—3)and one long-chain oligomeric donor(BTDT)4-RD,are facilely synthesized by an atom-and step-economical,and labor-saving direct C—H arylation(DACH)reaction(i.e.,C—H/C—Br cross coupling).Note that(BTDT)4-RD involving five CPDT,four BT and two rhodamine(RD)building blocks is the longest oligomeric donor in the fullerene-free OSC devices ever reported.The dependence of the structure-property-performance correlation of(BTDT)n-IC(n=1—3)and(BTDT)4-RD on theπ-conjugation lengths is thoroughly investigated by opto-electrochemical measurements,bulk heterojunction(BHJ)OSC devices and microscopies.The(BTDT)1-IC:PBDB-T and(BTDT)4-RD:Y6 BHJs achieve power conversion efficiencies of 9.14%and 4.51%,respectively.Our findings demonstrate that DACH reaction is a powerful tool to tune the opto-electronic properties and device performances by regulating the lengths ofπ-conjugated oligomers with varied numbers of repeating units.展开更多
基金Supported by the National Natural Science Foundation of China(No.52103232)the Natural Science Foundation of Zhejiang Province,China(Nos.LY24E030012,LY19E030006)。
文摘Cyclopentadithiophene(CPDT)-based polymers have emerged as promising research platforms for multi⁃color electrochromic materials due to their favorable color tunability.However,insufficient cyclic stability has hindered their translation into practical applications.In this study,two CPDT-based conjugated polymers with distinct substituent groups were designed and synthesized:PCPDT-Ph(copolymerized with unsubstituted benzene units)and PCPDT-PhOMe(copolymerized with dimethoxy-substituted benzene units).The influence of dimethoxy substitution on the electrochromic properties and stability of the polymers was systematically investigated.Electro⁃chemical and electrochromic characterizations demonstrated that the electron-donating ability of the dimethoxy groups not only effectively regulated the polymer’s intrinsic properties but also significantly enhanced its cycling stability.Compared with PCPDT-Ph,PCPDT-PhOMe exhibited a reduced onset oxidation potential from 0.66 V(vs.Ag/AgCl)to 0.46 V,an upshifted highest occupied molecular orbital(HOMO)energy level,and a narrowed optical band gap(calculated theoretically)from 1.73 eV to 1.61 eV.The PCPDT-PhOMe film showed magenta in the neutral state and transparency in the oxidized state,with a color difference(ΔE*a b)of 46.36.The coloring/bleaching response times were measured as 0.7/0.6 s,and the optical contrast retention reached 84%after 1000 cycles,outperforming the PCPDT-Ph film(79.5%retention after 500 cycles).Additionally,it exhibited a coloration efficiency of 543.9 cm^(2)/C,demonstrating favorable comprehensive electrochromic performance.Electrochromic devices assembled with PCPDT-PhOMe achieved reversible switching between magenta and transparent states,with a response time of≤1.0 s and a contrast retention of 71%after 30000 cycles,indicating good stability.This work clarifies the role of substituent electronic effects in regulating the electrochromic properties of CPDT-based polymers,providing experimental basis and theoretical support for the molecular design of solution-processable thiophene-based electrochromic materials.Furthermore,it validates the potential application of PCPDT-PhOMe in smart windows,electronic displays,and other related fields.
基金financially supported by the 973 Project(Nos.2009CB623601and2009CB930603)the Science Fund for Creative Research Groups(No.20921061)the National Natural Science Foundation of China(Nos.51173179,20904055 and21074130)
文摘In this paper, a new D-A copolymer, PFDBCPDT, which consists of benzo-2,1,3-thiadiazole as acceptor units and cyclopentadithiophene and fluorene as donor units, was synthesized. The thermal, electrochemical, photophysical and photovoltaic properties of PFDBCPDT were studied. PFDBCPDT showed a low optical band gap of 1.84 eV, and relatively low HOMO level of-5.69 eV. The best device performance was obtained by PFDBCPDT/PC61BM （1：3） with 0.5 vol% DIO. The device exhibited a power conversion efficiency of 3.06%, with a relatively high open circuit voltage of 0.87 eV.
基金The National Natural Science Foundation of China(No.21374075)is appreciated for financial supports.
文摘Main observation and conclusion A series of all-donor type alternating(D1-D2)monodisperse oligomers based on cyclopentadithiophene(CPDT)and 1,4-difluoro-benzene(DFB)with gradually increasing chain lengths containing 3 to 15 monomers were successfully synthesized via one-pot C-H direct arylation reaction.As confirmed by various structural characterizations,all these long-chain oligomers are monodispersed with defined structures.The length-dependent optical and electrochemical properties with the evolution from the shortest oligomer(01)to the longest oligomer(07)and their parent polymer P1 have been studied in details.By simply tuning the mixing ratio of discrete oligomers,the photoluminescence(PL)in a wide range of color emissions extending to near-white can be facilely modulated,ilus-trating the potential of these monodisperse conjugated oligomers for light emission application.The atom-,step-and pot-economic synthetic strategy here developed will open the door toward efficient and controllable synthesis ofπ-conjugated oligomers for accu-rate structure-property relationship study and optic&electronic device applications.
基金The National Natural Science Foundation of China(No.22169009)Jiangxi Provincial Natural Science Foundation(No.20212ACB204007)Jiangxi Provincial Key Laboratory of Functional Molecular Materials Chemistry(20212BCD42018)are appreciated for financial support。
文摘The rapid synthesis of structurally complicated electron donors&acceptors still remains a major challenge in organic solar cells(OSC).In this work,we developed a highly efficient strategy to access long-chain oligomeric donor and acceptors for OSC applications.A series of cyclopentadithiophene(CPDT)and benzothiadiazole(BT)-basedπ-conjugated oligomers,i.e.,three oligomeric acceptors(BTDT)n-IC(n=1—3)and one long-chain oligomeric donor(BTDT)4-RD,are facilely synthesized by an atom-and step-economical,and labor-saving direct C—H arylation(DACH)reaction(i.e.,C—H/C—Br cross coupling).Note that(BTDT)4-RD involving five CPDT,four BT and two rhodamine(RD)building blocks is the longest oligomeric donor in the fullerene-free OSC devices ever reported.The dependence of the structure-property-performance correlation of(BTDT)n-IC(n=1—3)and(BTDT)4-RD on theπ-conjugation lengths is thoroughly investigated by opto-electrochemical measurements,bulk heterojunction(BHJ)OSC devices and microscopies.The(BTDT)1-IC:PBDB-T and(BTDT)4-RD:Y6 BHJs achieve power conversion efficiencies of 9.14%and 4.51%,respectively.Our findings demonstrate that DACH reaction is a powerful tool to tune the opto-electronic properties and device performances by regulating the lengths ofπ-conjugated oligomers with varied numbers of repeating units.
