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Impact of A‐D‐A Structured Dithienosilole and Phenoxazine based Small Molecular Material for Bulk Heterojunction and Dopant‐free Perovskite Solar Cells
摘要： In this communication, we have designed and synthesized a novel acceptor-donor-acceptor (A-D-A) structured small molecule Si-PO-2CN based on dithienosilole (DTS) as building block flanked by electron-rich Phenoxazine (POZ) units terminated with dicyanovinylene which showed unique electrochemical and photo-physical properties. Si-PO-2CN has been successfully employed in perovskite solar cells (PSCs) as well as in bulk hetero-junction organic solar cells (OSCs). The PSCs fabricated with dopant free Si-PO-2CN as hole-transport material (HTM) exhibited a power conversion efficiency (PCE) of 14.1% (active area 1.02 cm2). Additionally, PCE of 5.6% has been achieved for OSCs using Si-PO-2CN as p-type donor material when blended with PC71BM acceptor. The versatile application of Si-PO-2CN provides path way for further implementation of DTS based building blocks in solar cells for designing new molecules.
关键词： A-D-A structured,dopant-free perovskite solar cells,bulk heterojunction,phenoxazine,small molecular material,dithienosilole
更新于2025-09-11 14:15:04
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12.1: <i>Invited Paper:</i> Polarization control and optical efficiency improvement of light emitted from OLED using liquid crystalline luminophores
摘要： Highly circularly polarized (CP) light is generated by using a twisted conjugated polymer structure with a small amount of chiral molecules as the light emitting layer of the OLED. It is confirmed that the luminous efficiency is increased by 60% compared to the conventional OLED structure.
关键词： organic light emitting diodes,conjugated polymer,polarized emission,chiral dopant,Circular polarization
更新于2025-09-11 14:15:04
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High‐Performance Inverted Planar Perovskite Solar Cells Enhanced by Thickness Tuning of New Dopant‐Free Hole Transporting Layer
摘要： A new hole transporting material (HTM) named DMZ is synthesized and employed as a dopant-free HTM in inverted planar perovskite solar cells (PSCs). Systematic studies demonstrate that the thickness of the hole transporting layer can effectively enhance the morphology and crystallinity of the perovskite layer, leading to low series resistance and less defects in the crystal. As a result, the champion power conversion efficiency (PCE) of 18.61% with JSC = 22.62 mA cm?2, VOC = 1.02 V, and FF = 81.05% (an average one is 17.62%) is achieved with a thickness of ≈13 nm of DMZ (2 mg mL?1) under standard global AM 1.5 illumination, which is ≈1.5 times higher than that of devices based on poly(3,4-ethylenedioxythiophene)/poly(styrene sulfonic acid) (PEDOT:PSS). More importantly, the devices based on DMZ exhibit a much better stability (90% of maximum PCE retained after more than 556 h in air (relative humidity ≈ 45%–50%) without any encapsulation) than that of devices based on PEDOT:PSS (only 36% of initial PCE retained after 77 h in same conditions). Therefore, the cost-effective and facile material named DMZ offers an appealing alternative to PEDOT:PSS or polytriarylamine for highly efficient and stable inverted planar PSCs.
关键词： inverted planar structure,perovskite solar cells,dopant-free,hole transporting materials
更新于2025-09-11 14:15:04
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Polymeric, Cost-Effective, Dopant-Free, Hole Transport Materials for Efficient and Stable Perovskite Solar Cells
摘要： Perovskite solar cells (PSCs) have skyrocketed in the last decade to an unprecedented level due to its outstanding photoelectric properties and facile processability. However, the utilization of expensive hole transport materials (HTMs) and the inevitable instability instigated by the deliquescent dopants represent major concerns hindering further commercialization. Here, a series of low cost, conjugated polymers are designed and applied as dopant free HTMs in PSCs, featuring tuned energy levels, good temperature and humidity resistivity, and excellent photoelectric properties. Further studies highlight the critical and multifaceted roles of the polymers with respect to facilitating charge separation, passivating the surface trap sites of perovskite materials, and guaranteeing long-term stability of the devices. A stabilized power conversion efficiency (PCE) of 20.3% and remarkably enhanced device longevity are achieved using the dopant free P3 with a low concentration of 5 mg/mL, qualifying the devices as one of the best PSC systems constructed based on dopant-free HTMs so far. In addition, the flexible PSCs made based on P3 also exhibit a PCE of 16.2%. This work demonstrates a promising route towards commercially viable, stable and efficient PSCs.
关键词： perovskite solar cell,good stability,conjugated polymer,dopant free,hole transport material
更新于2025-09-11 14:15:04
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Coupled Halide-deficient and Halide-rich Reaction System for Doping in Perovskite Armed Nanostructures
摘要： Insights of Mn(II) doping in CsPbCl3-armed hexapod nanostructures is reported. These complex structures were typically formed in halide concentration tuned modulated reactions. Cores were first formed under halide deficient condition and with enriching halides; these were transformed to armed structures. Doping of Mn(II) was observed facilitated during the arm growth in the second stage of the reaction. These observations were supported with decoupled reactions with minimized and maximized halide concentrations carried out in separate reactions. However, less interference for the exciton to dopant energy transfer was noticed for the defect states created in halide-deficient medium, and the intensity of the dopant emission remained proportional to the amount of dopant inserted in the nanocrystals. Being this is an in situ observation in the coupled reactions of both poor and rich halide reaction systems, the finding would strengthen the understanding of doping in perovskite host nanocrystals.
关键词： CsPbCl3,hexapod nanostructures,Mn(II) doping,halide concentration,dopant emission
更新于2025-09-11 14:15:04
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Mitigating Plasmonic Absorption Losses at Rear Electrodes in High‐Efficiency Silicon Solar Cells Using Dopant‐Free Contact Stacks
摘要： Although charge-carrier selectivity in conventional crystalline silicon (c-Si) solar cells is usually realized by doping Si, the presence of dopants imposes inherent performance limitations due to parasitic absorption and carrier recombination. The development of alternative carrier-selective contacts, using non-Si electron and hole transport layers, has the potential to overcome such drawbacks and simultaneously reduce the cost and/or simplify the fabrication process of c-Si solar cells. Nevertheless, devices relying on such non-Si contacts with power conversion efficiencies (PCEs) that rival their classical counterparts are yet to be demonstrated. In this study, one key element is brought forward toward this demonstration by incorporating low-pressure chemical vapor deposited ZnO as the electron transport layer in c-Si solar cells. Placed at the rear of the device, it is found that rather thick (75 nm) ZnO film capped with LiFx/Al simultaneously enables efficient electron selectivity and suppression of parasitic infrared absorption. Next, these electron-selective contacts are integrated in c-Si solar cells with MoOx-based hole-collecting contacts at the device front to realize full-area dopant-free-contact solar cells. In the proof-of-concept device, a PCE as high as 21.4% is demonstrated, which is a record for this novel device class and is at the level of conventional industrial solar cells.
关键词： ZnO,plasmonic absorption,c-Si solar cells,carrier-selective contacts,dopant-free contacts
更新于2025-09-11 14:15:04
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Side-Chain Engineering of Donor–Acceptor Conjugated Small Molecules As Dopant-Free Hole-Transport Materials for Efficient Normal Planar Perovskite Solar Cells
摘要： Simultaneously improving efficiency and stability, which are particularly crucial factors for the commercialization of perovskite solar cells (PSCs), remains a major challenge. For high efficiency normal PSCs, the development of stable dopant-free hole-transport materials (HTMs) seems imperative. Here, we developed potential donor-acceptor (D-A) small molecules (BTTI) as HTMs for normal planar PSCs. Through tailoring its alkyl side chain length as BTTI-C6, BTTI-C8 and BTTI-C12, our results show that upon shortening the side chain of BTTI, the hole mobility, film-forming capability and resultant device performance were remarkably improved, with device conversion efficiencies of 19.69% for BTTI-C6, 18.89% for BTTI-C8 and 17.49% for BTTI-C12. Meanwhile, compared to those made with the routine doped Spiro-OMeTAD, devices based on our dopant-free HTMs exhibited significantly improved stability. This work paves the way to the development of effective dopant-free HTMs for high performance PSCs.
关键词： Perovskite solar cells,Donor-acceptor conjugated small molecules,Dopant-free,Hole-transport materials,Side chain engineering
更新于2025-09-11 14:15:04
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Influence of back gate voltage on electrical transport in Zn <sub/>1-(y+x)</sub> (Al <sub/>x</sub> ,Eu <sub/>y</sub> )O thin films
摘要： We investigated the back gate voltage (VBG) dependent electrical conductivity of Zn1-(y+x)(Alx,Euy)O (x = 0.00, 0.01; y = 0.00, 0.01, 0.02 and 0.05) thin films. Zn1-(y+x)(Alx,Euy)O (x = 0.00, 0.01; y = 0.00, 0.01, 0.02 and 0.05) thin films were synthesized with combining sol-gel and spin coating techniques. Electrical conductivity measurements was monitored by longitudinal conductivity curves of Eu doped (Zn, Al)O thin films. The measurements show a sharp decrease or increase in conductivity of Eu doped (Zn, Al)O thin films by an applied ±VBG, which was not observed for Al doped ZnO thin films. The Eu amount in (Zn, Al)O lattice was the key parameter to manage the change in conductivity by ±VBG. The highest increase in conductivity by applied ±VBG was observed for 1 mol% Eu-doped Zn1-(y+0.01)(Al0.01,Euy)O films, which also performed the highest longitudinal conductivity without a VBG. By applied VBG = ?100 V, the change ratio in conductivity reached up to 436% for 1 mol% Eu doped (Zn, Al)O thin films. The response to VBG were drastically decreased by increase in Eu amounts in the lattice, and furthermore no change in conductivity was observed for 5 mol% Eu doped (Zn, Al)O thin films.
关键词： dopant,oxide semiconductors,II–VI semiconductors,rare earth element,back gate voltage
更新于2025-09-11 14:15:04
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A differential Hall effect measurement method with sub-nanometre resolution for active dopant concentration profiling in ultrathin doped Si <sub/>1?</sub><i> <sub/>x</sub></i> Ge <i> <sub/>x</sub></i> and Si layers
摘要： In this paper, we present an enhanced differential Hall effect measurement method (DHE) for ultrathin Si and SiGe layers for the investigation of dopant activation in the surface region with sub-nanometre resolution. In the case of SiGe, which constitutes the most challenging process, we show the reliability of the SC1 chemical solution (NH4OH/H2O2/H2O) with its slow etch rate, stoichiometry conservation and low roughness generation. The reliability of a complete DHE procedure, with an etching step as small as 0.5 nm, is demonstrated on a dedicated 20 nm thick SiGe test structure fabricated by CVD and uniformly doped in situ during growth. The developed method is finally applied to the investigation of dopant activation achieved by advanced annealing methods (including millisecond and nanosecond laser annealing) in two material systems: 6 nm thick SiGeOI and 11 nm thick SOI. In both cases, DHE is shown to be a uniquely sensitive characterisation technique for a detailed investigation of dopant activation in ultra-shallow layers, providing sub-nanometre resolution for both dopant concentration and carrier mobility depth profiles.
关键词： contact resistance,sub-nanometre resolution,fully depleted silicon on insulator (FDSOI),carrier mobility,differential Hall effect,dopant activation,laser annealing
更新于2025-09-10 09:29:36
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Quantitative Aspects of PLAD Sidewall Doping Characterization by SIMS and APT
摘要： Application of atom probe tomography (APT) and 1.5D secondary ion mass spectrometry (SIMS) as complimentary techniques to study fin sidewall doping by plasma implantation (PLAD) is the focus of this paper. Unlike planar transistors, characterization of 3D devices both by SIMS and APT requires sample preparation via trench backfill with α-Si, or other material, via chemical vapor deposition or atomic layer deposition process due to high aspect ratio of test structures. Certain artifacts with adverse impacts on quantitative results encountered in this study are discussed.
关键词： SIMS,PLAD,APT,dopant
更新于2025-09-10 09:29:36