Auxiliary Electron Acceptor Research Articles

Asymmetrical Diketopyrrolopyrrole Derivatives with Improved Solubility and Balanced Charge Transport Properties.

The diketopyrrolopyrrole (DPP) unit represents one of the building blocks more widely employed in the field of organic electronics; in most of the reported DPP-based small molecules, this unit represents the electron acceptor core symmetrically coupled to donor moieties, and the solubility is guaranteed by functionalizing lactamic nitrogens with long and branched alkyl tails. In this paper, we explored the possibility of modulating the solubility by realizing asymmetric DPP derivatives, where the molecular structure is extended in just one direction. Four novel derivatives have been prepared, characterized by a common dithyenil-DPP fragment and functionalized on one side by a thiophene unit linked to different auxiliary electron acceptor groups. As compared to previously reported symmetric analogs, the novel dyes showed an increased solubility in chloroform and proved to be soluble in THF as well. The novel dyes underwent a thorough optical and electrochemical characterization. Electronic properties were studied at the DFT levels. All the dyes were used as active layers in organic field effect transistors, showing balanced charge transport properties.

Screening efficient organic dyes based on ZL001 by modulating its auxiliary electron acceptor for dye-sensitized solar cells: A theoretical perspective

Based on ZL001 dye, in this work a series of novel organic dyes (denoted M1-M9) were designed by modulating its auxiliary electron acceptors, and then their electronic, optical, and photovoltaic properties were systematically estimated by density functional theory (DFT)/time-dependent DFT (TD-DFT) calculations coupled with Marcus charge transfer model. Results showed that the modulation of auxiliary electron acceptor can efficiently dominate the HOMO-LUMO gap, and dramatically enhance the optical absorption. By exactly estimating the influence of electron injection/recombination on the photocurrent density, the power conversion efficiency (PCE) for ZL001 was estimated to be about 12.90 % with Voc=837 mV, Jsc=21.92 mA·cm−2, and FF= 0.703 at the standard solar radiation, which is in good agreement with its measured value of 12.8 ± 0.1 % (Voc=887±6 mV, Jsc=20.57±0.18 mA·cm−2, and FF= 0.700±0.004). With the same scheme, the predicted PCE value for most of designed dyes was higher than that of ZL001, illuminating that our molecular design is successful. In comparison with ZL001, three newly designed dyes (M7, M8, and M9) with thieno[3,4-b] pyrazine (TPZ), 2,5-dimethyl-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione (DPP), and 5,5′-bithieno[3,4-b]pyrazine (BPZ) as the auxiliary electron acceptor exhibit high PCE values of 19.45 %, 17.63 % and 24.64 % respectively at the AM1.5 G conditions, suggesting that these three dyes are promising candidates for solar cell applications.

Screening novel candidates of ZL003-based organic dyes for dye-sensitized solar cells by modifying auxiliary electron acceptors: A theoretical study

In this work, a series of ZL003-based free-metal sensitizers with the donor-acceptor-π- conjugated spacer-acceptor (D-A-π-A) structure were designed by modifying auxiliary electron acceptors for the potential application in dye-sensitized solar cells. The energy levels of frontier molecular orbitals, absorption spectra, electronic transition, and photovoltaic parameters for all studied dyes were systematically evaluated using density functional theory (DFT)/time-dependent DFT calculations. Results illustrated that thienopyrazine (TPZ), selenadiazolopyridine (SDP), and thiadiazolopyridine (TDP) are excellent electron acceptors, and dye sensitizers functionalized by these acceptors have smaller HOMO-LUMO gaps, obviously red-shifted absorption bands and stronger light harvesting. The present study revealed that the photoelectric conversion efficiency (PCE) of ZL003 is around 13.42 % with a JSC of 20.21 mA·cm−2, VOC of 966 mV and FF of 0.688 under the AM 1.5G sun exposure, in good agreement with its experimental value (PCE = 13.6 ± 0.2 %, JSC = 20.73 ± 0.20 mA·cm−2, VOC = 956 ± 5 mV, and FF = 0.685 ± 0.005.). With the same procedure, the PCE values for M4, M6, and M7 were estimated to be as high as 19.93 %, 15.38 %, and 15.80 % respectively. Hence, these three dyes are expected to be highly efficient organic sensitizers applied in practical DSSCs.

Sensitizers of Metal Complexes with Sulfur Coordination Achieving a Power Conversion Efficiency of 12.89.

In the study to improve the light absorption range and intensity of dye sensitizers in the visible region and promote their photovoltaic performance, five novel polymeric metal complexes with sulfur coordination (BDTT-VBT-Ni, BDTT-VBT-Cu, BDTT-VBT-Zn, BDTT-VBT-Cd, and BDTT-VBT-Hg) to be used as D-A-π-A motif dye sensitizers were designed, synthesized, and characterized. In these polymeric metal complexes with sulfur coordination, the metal complexes with sulfur coordination of benzodithiophene derivatives are used as auxiliary electron acceptors, 8-quinolinol derivatives are used as π-bridge and electron acceptors, and thienylbenzene-[1,2-b:4,5-b'] dithiophene (BDTT) are used as electron donors. The effect of different metal complexes with sulfur coordination on the photovoltaic performance of dye sensitizers has been systematically studied. Under AM 1.5 irradiation (100 mW cm-2), the devices of dye-sensitized solar cells (DSSCs) based on five polymeric metal complexes with sulfur coordination exhibited a short-circuit current density (Jsc) of 13.43, 15.07, 18.00, 18.99, and 20.78 mA cm-2, respectively, and their power conversion efficiencies (PCEs) were 7.10, 8.59, 10.68, 11.23, and 12.89%, respectively, and their thermal decomposition temperatures (Td) were 251, 257, 265, 276, and 277 °C, respectively. The result shows that the Jsc and PCE of five polymeric metal complexes increase by degrees, and the PCE of BDTT-VBT-Hg is up to 12.89%, which is because of the strength of the coordination bonds between Ni(II), Cu(II), Zn(II), Cd(II), and Hg(II) and sulfur increases in turn so that the electron-withdrawing ability and electron-transfer ability of auxiliary electron acceptors is enhanced. These results provide a new way to develop stable and efficient metal complexes with sulfur coordination dye sensitizers in the future.

Novel Metal Complexes Unit of Phenanthroline Derivative for Being Used as Auxiliary Electron Acceptor in Dye Sensitizer Molecules

AbstractDonor‐acceptor‐π bridge‐acceptor (D−A−π−A) motif dyes are promising dye sensitizers in dye‐sensitized solar cells (DSSCs). In this study, to strengthen with‐drawing electron force of the auxiliary electron acceptors(A) in D−A−π−A motif dye sensitizers, the metal complexes unit is be used as auxiliary electron acceptor(A) instead of organic electron‐withdrawing monomer. The four polymeric metal complexes were designed, synthesized, and characterized, which used metal complexes of phenanthroline derivatives as auxiliary acceptors (A), benzodithiophene‐dithiophene derivatives (BDTT) as donors (D), and 8‐hydroxyquinoline derivatives as π‐bridges and acceptors of the dye sensitizers, and have been used for dye sensitizers. Under AM 1.5 G (100 mW cm−2), the photovoltaic test results indicated that the short‐circuit photocurrent density (Jsc) of the DSSCs based four polymeric metal complexes are 11.26, 13.68, 14.42 and 15.57 mA cm−2and power conversion efficiency (PCE) are 5.96 %, 7.83 %, 8.07 %, 9.28 % respectively. BothJscandPCEvalue of the four polymeric metal complexes increased in order. This may be due to the fact that larger radius of metal ion under the same change number can enhance the coordination bond and cause stronger electron‐withdrawing ability of auxiliary acceptor and stronger charge‐transfer ability between the donor and the acceptor, which results in higherJscand higherPCEof the polymeric complex dye sensitizer.

Solution‐Processable Pure‐Red Multiple Resonance‐induced Thermally Activated Delayed Fluorescence Emitter for Organic Light‐Emitting Diode with External Quantum Efficiency over 20 %

AbstractDeveloping solution‐processable red organic light‐emitting diodes (OLEDs) with high color purity and efficiency based on multiple resonance thermally activated delayed fluorescence (MR‐TADF) is a formidable challenge. Herein, by introducing auxiliary electron donor and acceptor moieties into the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) distributed positions of multiple resonance skeleton simultaneously, an effective strategy to obtain red MR‐TADF emitters was represented. The proof‐of‐the‐concept molecule BN‐R exhibits a narrowband pure‐red emission at 624 nm, with a high luminous efficiency of 94 % and a narrow bandwidth of 46 nm. Notably, the fabricated solution‐processable pure‐red OLED based on BN‐R exhibits a state‐of‐the‐art external quantum efficiency over 20 % with the Commission Internationale de I’Éclairage coordinates of (0.663, 0.337) and a long operational lifetime (LT50) of 1088 hours at an initial luminance of 1000 cd m−2.

Solution-Processable Pure-Red Multiple Resonance-induced Thermally Activated Delayed Fluorescence Emitter for Organic Light-Emitting Diode with External Quantum Efficiency over 20.

Developing solution-processable red organic light-emitting diodes (OLEDs) with high color purity and efficiency based on multiple resonance thermally activated delayed fluorescence (MR-TADF) is a formidable challenge. Herein, by introducing auxiliary electron donor and acceptor moieties into the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) distributed positions of multiple resonance skeleton simultaneously, an effective strategy to obtain red MR-TADF emitters was represented. The proof-of-the-concept molecule BN-R exhibits a narrowband pure-red emission at 624 nm, with a high luminous efficiency of 94% and a narrow bandwidth of 46 nm. Notably, the fabricated solution-processable pure-red OLED based on BN-R exhibits a state-of-the-art external quantum efficiency over 20% with the Commission Internationale de I'Éclairage coordinates of (0.663, 0.337) and a long operational lifetime (LT50) of 1088 hours at an initial luminance of 1,000 cd m-2.

Novel polymeric metal complexes of salicylaldehyde schiff base derivative being used for dye sensitizer

For studying the effect of metal complexes used as auxiliary electron acceptors of dye sensitizers in dye sensitized solar cell (DSSC) on photovoltaic performance, four polymeric metal complexes, which adopt 1,4-dioctyloxy-2,5-dibromobenzene or thienylbenzo-[1,2-b:4,5-b']-dithiophene (BDTT) as electron donor (D), salicylaldehyde schiff base derivatives as auxiliary acceptor (A), 8-hydroxyquinoline derivative as π bridge and acceptor (A), were designed, synthesized and characterized. The influence of different donor and metal complexes of the four dye sensitizers on performance were discussed by determining their thermal, photophysical, electrochemical and photovoltaic properties. The DSSC devices based on the four polymeric metal complexes PBDTT–SF–Cd, PBDTT–SF–Cu, PPV-SF-Cd and PPV-SF-Cu exhibited a short-circuit photocurrent density (Jsc) of 14.94 mA cm−2, 14.86 mA cm−2, 10.23 mA cm−2 and 9.80 mA cm−2 as well as acquired power conversion efficiency (PCE) of 8.59%, 8.45%, 5.29% and 4.77% respectively under the AM 1.5 irradiation (100 mW cm−2). Both Jsc and PCE value of the four polymeric metal complexes are in a decreased order. The phenomenon is attributed to not only the variable strength of coordination bond formed between metal ion and ligand, which can be affected by the radius and charge number of metal ion, but also the better electron-donating ability of BDTT. In common charge number, bigger radius of metal ion will cause more powerful coordination bond as well as greater electron-withdrawing ability of auxiliary acceptor and charge-transfer ability between donor and acceptor. This work provides a distinctive perspective for the design of D-A-π-A motif complexes in DSSC application.

Novel metal complexes of pyridineimine derivative used as auxiliary electron acceptor of D-(A-π-A)2 motif dye sensitizer: synthesis and photovoltaic application

Novel metal complexes of pyridineimine derivative used as auxiliary electron acceptor of D-(A-π-A)2 motif dye sensitizer: synthesis and photovoltaic application

Novel Polymeric Metal Complexes for Dye Sensitizer: Synthesis and Photovoltaic Performances

Four novel polymeric metal complexes with a D–A–π–A motif, BDTT-PY-Cd, BDTT-PY-Zn, BDTT-PY-Cu and BDTT-PY-Ni, were designed, synthesized and characterized. These polymeric metal complexes were made up with Cd(II), Zn(II), Cu(II), Ni(II) complexes, thienylbenzo-[1,2-b:4,5-b'] dithiophene (BDTT) and the 8-quinolinol derivative, which were used severally as dye sensitzers’ auxiliary electron acceptors (A), electron donor (D) and π bridges as well as the acceptors (A). Under AM 1.5 irradiation (100 mW cm−2), the devices of dye sensitized solar cells (DSSC) based on four polymer complexes exhibited short-circuit photocurrent densities (Jsc) of 17.45 mA cm−2, 14.75 mA cm−2, 13.94 mA cm−2 and 12.00 mA cm−2, as well as attractive power conversion efficiencies (PCE) of were 9.73%, 8.02%, 6.82% and 6.12%, respectively. The photovoltaic conversion efficiency (PCE) and short-circuit photocurrent density (Jsc) of BDTT-PY-Cd, BDTT-PY-Zn, BDTT-PY-Cu and BDTT-PY-Ni decrease in order because the radius and charge number of the metal ion affect the strength of the coordination bond between the metal ion and the ligand. These results provides a new way of development for efficient and stable dye sensitizers in the future.

Efficient improvement of W05‐based dyes by inserting auxiliary electron acceptors for dye‐sensitized solar cells: A theoretical investigation

AbstractTo develop efficient sensitizers, five novel metal‐free dyes were designed based on one of the best dyes W05 by inserting auxiliary electron acceptors. The photovoltaic performance of new dyes was studied by density functional theory (DFT) and time‐dependent DFT (TDDFT) calculations in order to shed light on how the auxiliary electron acceptor influences on the photovoltaic performances. Results illustrated that the insertion of auxiliary electron acceptors can narrow the HOMO‐LUMO gap, red‐shift the light absorption band, and enhance the sunlight harvesting. By estimating three important photovoltaic parameters, the photoelectric conversion efficiency (PCE) of W05 was estimated to be about 8.96%, in good agreement with its experimental value of 9.22%, indicating that the scheme calculated the photovoltaic parameters is reliable. Interestingly, the estimated PCE values for designed dyes are superior to that of W05, suggesting that the molecular design is reasonable. Especially 5, its PCE was predicted to be as high as 14.07%, indicating that 5 is a promising sensitizer candidate for DSSC applications.

Novel metal complexes for D‐(A‐π‐A)2motif dye sensitizer: Synthesis and photovoltaic application

Four metal complexes BDTT‐PCd, BDTT‐PZn, BDTT‐PCu, and BDTT‐PCo with the symmetrical structure were designed, synthesized, and characterized, which would be used as D‐(A‐π‐A)2motif dye sensitizers. These complexes adopt Cd(II), Zn(II), Cu(II), and Co(II) complexes as auxiliary electron acceptors (A), thienylbenzo[1,2‐b:4,5‐b′]dithiophene (BDTT) as electron donor (D), and the 8‐quinolinol derivative as the π bridge and the acceptor (A) of D‐(A‐π‐A)2motif dye sensitizers. The photophysical, electrochemical, and photovoltaic properties of these complexes have been investigated. The four complexes‐based dye‐sensitized solar cells (DSSCs) device exhibited a short‐circuit photocurrent density (Jsc) of 17.51, 17.02, 15.07, and 14.38 mA cm−2and an attractive power conversion efficiency (η) of 8.82%, 8.32%, 8.03%, and 7.55%, respectively, under the AM 1.5 irradiation (100 mW cm−2). The photovoltaic conversion efficiency (PCE) and the short‐circuit photocurrent density (Jsc) of BDTT‐PCd, BDTT‐PZn, BDTT‐PCu, and BDTT‐PCo are sequentially reduced; it attributed to the difference of the electron‐withdrawing ability of the auxiliary acceptor resulted by the difference of coordination abilities of metal ions Cd(II), Zn(II), Cu(II), and Co(II) with ligand. These results provide strong evidence that D‐(A‐π‐A)2motif complexes has great potential as promising photosensitizers in the applications of DSSCs.

Performable enhancement of C220-based dyes via inserting auxiliary electron acceptors for dye-sensitized solar cells: a theoretical investigation

Motivated by the exploration for high-performable sensitizers, in this work six novel organic donor–acceptor–π–spacer–acceptor (D–A–π–A) dyes were designed by inserting auxiliary electron acceptors into the C220 dye, and their photovoltaic performances were predicted by density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations coupled with the charge hopping model. Results revealed that the insertion of auxiliary electron acceptors can clearly stabilize the LUMO, narrow the HOMO–LUMO gap, and remarkably enhance the dye’s optical absorption. Based on the estimation for the rates and efficiencies in charge injection, recombination, and dye regeneration processes, the photoelectric conversion efficiency (PCE) of C220 dye was predicted to be about 10.39% under standard solar radiation, in line with its measured value of 10.1%, suggesting that our calculation scheme is reliable. With the same strategy, the predicted PCE values for the dye 2, 3, and 4, with BTD, BSD and DPP as auxiliary electron acceptors, are as high as 13.17, 14.05 and 15.70%, respectively; illuminating that these three dyes are potential sensitizers for TiO2 nanocrystalline solar cells, and worth further study by experiments.

Optimization of porphyrin dyes with a bulky triphenylamine donor for developing efficient dye-sensitized solar cells

To fabricate efficient dye-sensitized solar cells (DSSCs), three porphyrin dyes XW65−XW67 have been designed and synthesized using a bulky triphenylamine donor. Based on our previously reported dyes with a carbazole donor, a bulky triphenylamine unit was employed as the donor to synthesize XW65 with the aim to enhance the electron donating ability and suppress dye aggregation. As a result, XW65 shows enhanced photocurrent density (Jsc) and open circuit voltage (Voc), affording a high efficiency of 9.02%. On this basis, XW66 was synthesized with a methyl group introduced into the carboxyphenyl acceptor to further suppress dye aggregation and improve the Voc, achieving an enhanced efficiency of 9.23% with improved Voc of 849 mV and Jsc of 14.87 mA cm−2, which can be ascribed to the further suppressed dye aggregation and enhanced adsorption amount on the TiO2 film induced by the additional methyl group. To further improve the Jsc, a benzothiadiazole (BTD) unit has been introduced as the auxiliary acceptor to afford XW67, which exhibits a strikingly red-shifted monochromatic photon-to-electron conversion efficiency (IPCE) onset wavelength of 830 nm, obtaining the highest Jsc value of 15.83 mA cm−2 among the three dyes. Consequently, despite the sacrifice of Voc caused by the severe dye aggregation associated the extended conjugation framework, XW67 exhibits the highest efficiency of 9.43%. On this basis, cosensitization with WS-5 afforded elevated efficiencies of 10.07%, 10.38% and 10.13% for XW65−XW67, respectively, owing to the simultaneously enhanced Jsc and Voc. These results indicate that it is effective to develop efficient DSSCs based on cosensitization of optimized porphyrin dyes containing a bulky triphenylamine donor, a methyl group on the carboxyphenyl acceptor, and an auxiliary electron acceptor.

Novel DPP derivatives functionalized with auxiliary electron-acceptor groups and characterized by narrow bandgap and ambipolar charge transport properties

Four novel diketopyrrolopyrrole (DPP) derivatives have been synthesized and characterized: the dyes are based on a DPP electron acceptor core symmetrically functionalized with donor bi-furyl moieties and end capped with four different auxiliary electron-acceptor groups. Because of the alternation along the molecular backbone of electron acceptor and donor groups, all the dyes are characterized by optical absorption maxima approaching or exceeding 700 nm. In the solid state, this optical behavior determines for all the dyes a very low optical bandgap ranging from 1.57 eV to 1.29 eV, while electrochemical characterization shows a clear dependence of the LUMO energies on the strength of the auxiliary electron-acceptor groups. All the dyes are characterized by stable LUMO energies suitable for their application as n-type semiconductors. Organic field-effect transistors based on the reported compounds display actually n-type behavior and, in three cases, a very interesting and balanced ambipolar charge transport behavior was moreover observed.

The improvement of photovoltaic performance of quinoline-based dye-sensitized solar cells by modification of the auxiliary acceptors

Three new dyes containing diphenylamine as electron donor, benzene (BIM1), benzothiadiazole (BTD) (BIM2) and N-ethylhexylbenzotriazole (BTZ) (BIM3) as auxiliary electron acceptors, quinoline as π-bridge and cyanoacrylic acid as anchoring group were synthesized in D-A-π-A structure for use in dye-sensitized solar cells (DSSCs). The optical, electrochemical, theoretical and photovoltaic methods were performed to understand the auxiliary acceptor influence on the performance of these dyes. Compared to the other dyes, the DSSC with dye BIM3 slightly increases the open circuit voltage (Voc) owing to the retardation of charge recombination by BTZ. However, replacement of benzene or BTZ by BTD unit causes a large red shift of the absorption spectra, leading BIM2 cell to produce the highest short circuit current density (Jsc). Thus, among the three D-A-π-A dyes, BIM2 is determined to be the most efficient dye, which reached a Voc of 0.627 V and Jsc of 11.53 mA cm–2, corresponding to an overall power conversion efficiency of 5.21 % in the presence of chenodeoxycholic acid (CDCA) as the coadsorbent. These results suggest that the insertion of benzothiadiazole as auxiliary acceptor into quinoline-based D-A-π-A dyes can effectively improve photovoltaic performance of DSSCs.

Solar cells sensitized with porphyrin dyes with a carbazole donor: The effects of an auxiliary benzothiadiazole acceptor and bulky substituents on the donor

Three porphyrin sensitizers XW54–XW56 containing a carbazole donor have been designed and synthesized by introducing a benzothiadiazole (BTD) unit as the auxiliary electron acceptor to extend the absorption spectra and/or bulky dihexyloxyphenyl groups into the carbazole unit to suppress dye aggregation and improve the photovoltage (Voc). The BTD unit incorporated in XW54 obviously broadens and red-shifts the absorption threshold to ca. 700 nm, as compared with that of 650 nm observed for XW1. Thus, XW54 exhibits a much broader monochromatic photon-to-electron conversion efficiency (IPCE) spectrum with an extremely red-shifted onset wavelength of 780 nm, resulting in a photocurrent density (Jsc) of 11.60 mA cm−2, higher than that of XW1. Unfortunately, the Voc value was decreased owing to the more severe dye aggregation caused by the large conjugation framework induced by the presence of the BTD unit. As a result, XW54 shows an efficiency of 6.26%, slightly higher than that of 6.11% obtained for XW1. On the other hand, with the bulky dihexyloxyphenyl donor groups introduced to XW55, a highest Voc of 860 mV was achieved, which can be ascribed to the efficient prevention of charge recombination and suppression of dye aggregation. Thus, XW55-based cells exhibit an improved efficiency of 6.60%. On the basis of XW54 and XW55, two bulky dihexyloxyphenyl groups and a BTD unit were simultaneously introduced to XW56, affording a highest efficiency of 7.03%, with the Jsc and Voc values of 12.5 mA cm−2 and 785 mV, respectively. These results compose a novel approach for developing efficient dye-sensitized solar cells (DSSCs) by simultaneously introducing bulky dihexyloxyphenyl groups and a benzothiadiazole unit, which may synergistically broaden the absorption spectra and suppress the dye aggregation, resulting in improved photocurrent and photovoltage.

Theoretical investigation of auxiliary electronic acceptors in modifying D-D-π-A sensitizers for dye-sensitized solar cells.

In light of the performance of the SD2 pigments in DSSC, in order to expand the absorption spectral scope, decrease the energy difference between the highest occupied and the lowest unoccupied molecular orbitals, with SD2 dye molecular electron donor and electron acceptor as the fundamental framework, the indole fragment and thiophene derivative in the prototype dye molecule were replaced by the two π-bridges (labeled PA, PB, respectively) and the four auxiliary electron acceptors (labeled A1, A2, A3, A4, respectively). For the sake of characterizing dye molecules as thoroughly as possible in DSSC, the frontier orbital energy levels, ultraviolet absorption spectra, natural bond orbital analysis, intramolecular charge transfer, charge and hole reorganization energies, parameters influencing the short-circuit current density and the open-circuit photovoltage for these eight individual dye molecules are carried out to try to fully characterize the properties of these dye molecules. According to these computational results of physical quantities and based on the performance of these dye molecules in the above aspects, in this paper, six free molecular models were picked out to combine with titanium dioxide cluster to calculate their geometrical structures, frontier orbital distributions, electron excitation energies, ultraviolet absorption spectra and the composition of the electronic transitions in chloroform solvent with polarizable continuum model. The results of these calculations show that the PA-A2 and PB-A4 dye molecule has better properties in electron transfer and spectral absorption range before and after the adsorption on the titanium dioxide.

T-shaped D−π−A−(π−A)2 chromophores with two auxiliary electron acceptors

A series of tripodal push-pull chromophores based on central indan-1,3-dione scaffold has been designed and synthesized by Knoevenagel condensation and Pd-catalyzed Suzuki-Miyaura cross-coupling reaction. Target molecules possess D−π−A−(π−A)2 extraordinary T-shaped structural arrangement. The electron donor attached at C2 position as well as the peripheral acceptor branches at C4 and C7 positions of the parent indan-1,3-dione have been systematically modified to achieve property tuning. Fundamental thermal and optoelectronic properties have been investigated by differential scanning calorimetry, electrochemistry, UV/Vis absorption spectroscopy, and DFT calculations. Based on the experimental and theoretical data, we herewith discuss thorough structure–property relationships.

Effect on photovoltaic performance of D–A–π–A motif polymer dye sensitizers by adopting the complex of metal with diamine as auxiliary electron acceptor

Donor–acceptor–π bridge–acceptor (D–A–π–A) dyes are promising sensitizers in dye-sensitized solar cells (DSSCs). With the aim to obtain high conversion efficiencies solar cells, three novel D–A–π–A efficient sensitizers coded PIDT–NCo, PIDT–NZn and PIDT–NCd had been synthesized and applied to DSSCs. These sensitizers adopting Co(II), Zn(II) or Cd(II) complexes as auxiliary electron acceptors (A), indacenodithiophene (IDT) derivatives as electron donor (D) and 8-quinolinol derivative as π bridge and acceptor (A). The results of photovoltaic test indicated that the three polymeric metal complex dye sensitizers have relatively higher performance among polymer dye sensitizers, and the device sensitized by PIDT–NCd shows the highest power conversion efficiency of 6.43% under simulate AM 1.5 G solar irradiation. Besides all dyes exhibited excellent thermal stability (Td > 320 °C). The research data have potential values for the development of coordination chemistry and provided a brand new idea to design efficient polymer dyes for DSSCs.