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Nd-Cr co-doped BiFeO3 thin films for photovoltaic devices with enhanced photovoltaic performance
摘要： BiFeO3 films and Nd-Cr co-doped BiFeO3 films were prepared by sol-gel method followed by spinning process on fluorine-doped tin oxide glass substrates. By testing the ultraviolet-visible absorption spectra, it was found that Nd-Cr co-doping will increase the light absorption rate of the film and reduce the optical band gap. The reduced bandgap can facilitate the transport of carriers. After Nd-Cr co-doping, the leakage current of the film is effectively reduced, which is near four orders of magnitude lower than the leakage current density of the pristine BiFeO3 film. The reduction of leakage current will enhance the ferroelectric polarization. The enhancement of ferroelectric polarization is more favorable for the separation of photogenerated carriers. Compared with the pristine BiFeO3 film, the short circuit photocurrent density, open circuit photovoltage and power conversion efficiency of Nd-Cr co-doped BiFeO3 film are all clearly improved. The Nd-Cr co-doped BiFeO3 films exhibited largely enhanced photovoltaic property, which favored the practical application of BiFeO3-based films in photovoltaic devices.
关键词： Element doping,Thin films,Ferroelectric property,Photovoltaic property,Bismuth ferrite,Leakage current
更新于2025-09-23 15:19:57
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Elevated Photovoltaic Performance in Medium Bandgap Copolymers Composed of Indacenodi-thieno[3,2-b]thiophene and Benzothiadiazole Subunits by Modulating the ??-Bridge
摘要： Two random conjugated polymers (CPs), namely, PIDTT‐TBT and PIDTT‐TFBT, in which indacenodithieno[3,2‐b]thiophene (IDTT), 3‐octylthiophene, and benzothiadiazole (BT) were in turn utilized as electron‐donor (D), π‐bridge, and electron‐acceptor (A) units, were synthesized to comprehensively analyze the impact of reducing thiophene π‐bridge and further fluorination on photostability and photovoltaic performance. Meanwhile, the control polymer PIDTT‐DTBT with alternating structure was also prepared for comparison. The broadened and enhanced absorption, down‐shifted highest occupied molecular orbital energy level (EHOMO), more planar molecular geometry thus enhanced the aggregation in the film state, but insignificant impact on aggregation in solution and photostability were found after both reducing thiophene π‐bridge in PIDTT‐TBT and further fluorination in PIDTT‐TFBT. Consequently, PIDTT‐TBT‐based device showed 185% increased PCE of 5.84% profited by synergistically elevated VOC, JSC, and FF than those of its counterpart PIDTT‐DTBT, and this improvement was chiefly ascribed to the improved absorption, deepened EHOMO, raised μh and more balanced μh/μe, and optimized morphology of photoactive layer. However, the dropped PCE was observed after further fluorination in PIDTT‐TFBT, which was mainly restricted by undesired morphology for photoactive layer as a result of strong aggregation even if in the condition of the upshifted VOC. Our preliminary results can demonstrate that modulating the π‐bridge in polymer backbone was an effective method with the aim to enhance the performance for solar cell.
关键词： 2‐b]thiophene,random conjugated polymer,modulating π‐bridge,indacenodithieno[3,photovoltaic property
更新于2025-09-19 17:13:59
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Synthesis and Photovoltaic Effect of Electron-Withdrawing Units for Low Band Gap Conjugated Polymers Bearing Bi(thienylenevinylene) Side Chains
摘要： A novel (E)-5-(2-(5-alkylthiothiophen-2-yl)vinyl)thien-2-yl (TVT)-comprising benzo[1,2-b:4,5-b’]dithiophene (BDT) derivative (BDT-TVT) was designed and synthetized to compose two donor-acceptor (D-A) typed copolymers (PBDT-TVT-ID and PBDT-TVT-DTNT) with the electron-withdrawing unit isoindigo (ID) and naphtho[1,2-c:5,6-c’]bis[1,2,5]thiadiazole (NT), respectively. PBDT-TVT-ID and PBDT-TVT-DTNT showed good thermal stability (360 °C), an absorption spectrum from 300 nm to 760 nm and a relatively low lying energy level of Highest Occupied Molecular Orbital (EHOMO) (?5.36 to –5.45 eV), which could obtain a large open-circuit voltage (Voc) from photovoltaic devices with PBDT-TVT-ID or PBDT-TVT-DTNT. The photovoltaic devices with ITO/PFN/polymers: PC71BM/MoO3/Ag structure were assembled and exhibited a good photovoltaic performance with a power conversion efficiency (PCE) of 4.09% (PBDT-TVT-ID) and 5.44% (PBDT-TVT-DTNT), respectively. The best PCE of a PBDT-TVT-DTNT/PC71BM-based device mainly originated from its wider absorption, higher hole mobility and favorable photoactive layer morphology.
关键词： polymer solar cells,photovoltaic property,benzo[1,2-b:4,5-b’]dithiophene,low band gap,bi(thienylenevinylene)
更新于2025-09-11 14:15:04
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Highly efficient perovskite solar cells based on a Zn2SnO4 compact layer
摘要： In the present work, a new reflux condensation route has been developed for synthesizing Zn2SnO4 film, which was first used as a compact layer in a perovskite solar cell (PSC), and achieved an efficiency of 20.1%. The high efficiency of PSC could be contributed to the following: i) As a compact layer in a PSC, Zn2SnO4 exhibits high electron mobility and has an appropriate energy band structure, resulting in the efficient extraction of carriers and transport of electrons; ii) the surface of the FTO substrate is completely covered by a Zn2SnO4 compact layer, and the direct contact between a perovskite layer and FTO is prevented, leading to significantly efficiently suppression of charge recombination. Consequently, the cell consisting of a Zn2SnO4 compact layer exhibits excellent photovoltaic performance.
关键词： Zn2SnO4,photovoltaic property,compact layer,perovskite solar cells,charge recombination,energy band structure
更新于2025-09-11 14:15:04