Chlorinated Thiazole-Based Low-Cost Polymer Donors for High Efficiency Binary and Ternary Organic Solar Cells

In this work,novel D-A alternating polymers(PJ-1,PJ-2,and PJ-3)with chlorinated benzodithiophene and chlorinated thiazole units were synthesized via gradual chlorination.These polymers could be obtained readily through a few concise synthesis steps.Among them,PJ-1 displayed desirable properties including energy levels,crystallinity,and charge transport capabilities.The binary and ternary organic solar cells(OSCs)fabricated based on PJ-1 displayed significant power conversion efficiency(PCE)of 15.02%and 19.12%,respectively,placing them among the highest reported for ternary OSCs.Notably,the PJ1-based devices also showcased one of the highest figure-of-merit values,indicating their promising potential for future applications.This study offers valuable insights and supports the development of costeffective and high-performance polymer donors for the generation of OSCs.

H^+ Passivation of Poly-Si Solar CellsProcessed by Different Annealing Processes

The effects of different annealing processes on the photovoltaic (PV) properties and the spectral response as well as minority carrier lifetime in the bulk of unanalyzed PF5 ion implantation poly-Si solar cells were investigated. The different hydrogen passivation effects of defects in poly-Si induced by three heat treatment processes are reported. We used RTA-rapid thermal annealing, YAG pulse laser annealing and CTSA-classical three-step annealing for this study. The results show that cells processed by RTA (800°C, 4 sec) achieved the best PV properties and spectral response among all annealed samples. Under this precess condition, no or few defects were induced in bulk. While RTA (>-850°C for 4 sec), CTSA as well as YAG laser processes induced defects of different nature and concentration in the bulk of cells. It is further shown that hydrogen ion implantation significantly improved, the performances of poly-Si cells. It is able to efficiently remove the YAG laser induced defects in bulk. However, it cannot completely passivate the defects induced by CTSA and RTA processes.

Low-cost dopant-free fluoranthene-based branched hole transporting materials for efficient and stable n-i-p perovskite solar cells

It has been widely recognized that hole transporting materials(HTMs)play a key role in the rapid progress of perovskite solar cells(PVSCs).However,common organic HTMs such as spiro-OMe TAD not only suffer from high synthetic costs,but also usually require the additional chemical doping process to improve their hole transport ability,which unfortunately induces the terrible stability issue.Therefore,it is urgent to develop low-cost dopant-free HTMs for efficient and stable PVSCs.In this work,we have successfully developed a new class of efficient dopant-free fluoranthene-based HTMs(TPF1–5)with quite low lab synthetic costs by combining donor-acceptor and branched structure designs.The detailed structure-property study revealed that tuning the twisted arms at different substitution sites would regulate the intermolecular interactions and film-forming ability,thereby significantly affecting the performance of the HTMs.By applying these HTMs in conventional PVSCs,the dopant-free TPF1-based devices not only achieved the best efficiency of 21.76%,which is comparable to that of the doped spiro-OMeTAD control devices,but also showed much better operational stability,which maintained over 87%of the initial efficiency under maximum power point tracking after 1038 h.

Semicrystalline Unfused Polymer Donors with Backbone Halogenation toward Cost-Effective Organic Solar Cells

Developing novel unfused building blocks with simple synthesis and low cost is essential to advance and enrich cost-effective poly-mer donors;however,it remains a challenge due to the lack of efficient molecular strategies.Herein,a class of low-cost and fully unfused polymer donors with precisely regulated backbone planarity via halogenation was designed and synthesized,namely PDTBTBz-2H,PDTBTBz-2F,and PDTBTBz-2Cl.These polymer donors possess a four-step synthesis route with over 80%yield from cheap raw chemicals comparable to existing low-cost polymer donors,such as PTQ10.Benefitting from the planar backbone via in-corporating the F…S non-covalent interactions,PDTBTBz-2F exhibits more robust J-type aggregation in solution and a long-ranged molecular stacking in film relative to PDTBTBz-2H and PDTBTBz-2Cl.Moreover,the systematical study of PDTBTBz-based organic so-lar cells(OSCs)reveals the close relationship between optimized molecular self-assembly and charge separation/transport regarding backbone halogenation when paired with the non-fullerene acceptor(Y6-BO-4F).As a result,the photovoltaic devices based on semicrystalline PDTBTBz-2F achieved a promising power conversion efficiency(PCE)of 12.37%.Our work highlighted the influence of backbone halogenation on the molecular self-assembly properties and a potential unfused backbone motif for further developing cost-effective OSCs.

Random Terpolymer Based on Simple Siloxane-functionalized Thiophene Unit Enabling High-performance Non-fullerene Organic Solar Cells

Incorporation of siloxane-functionalized units into polymers backbone has proven to be an efficient strategy to improve photovoltaic performance. In this work, a low-cost siloxane-containing unit was developed to construct a series of terpolymers, and the effects of siloxane on the polymer performance were systematically studied. Different contents of thiophene containing siloxane-functionalized side chain were introduced into PM6 to obtain a series of polymers(PM6, PM6-SiO-10, PM6-SiO-20 and PM6-SiO-30). The siloxane-functionalized side chains in polymers have only a slight effect on the absorption behavior and frontier molecular orbitals. However, when the siloxane content increased, the terpolymers' aggregation property decreased and the temperature-dependency increased, leading to improved donor-acceptor compatibility. The power conversion efficiency(PCE) based on PM6:Y6, PM6-SiO-20:Y6 and PM6-SiO-30:Y6 devices was 15.64%, 16.03% and 15.82%, respectively. In comparison, the active layer based on PM6-SiO-10:Y6 exhibits the most appropriate phase separation morphology, resulting in effective exciton dissociation, more balanced hole-electron transport and less recombination. Consequently, the highest PCE of 16.69% with an outstanding shortcircuit current density of 26.96 mA·cm^(-2) was obtained, which are one of the highest values for siloxane-functionalized polymer-based devices.This work demonstrates that finely controlling the content of siloxane-functionalized thiophene is beneficial for obtaining high-performance terpolymer donors and provides a novel and low-cost method to improve photovoltaic performance.

An asymmetric non-fused electron-deficient building block for low-cost polymer acceptor in all-polymer solar cells

The development of polymerized fused-ring small molecule acceptors(FRA-PAs) has boosted the performance of all-polymer solar cells(all-PSCs).However,these FRA-PAs suffer from lengthy synthesis steps and high production costs due to the high degree of synthetic complexity for fused-ring small molecule acceptors(FRAs).Furthermore,most FRA-PAs exhibit strong batch-to-batch variation,limiting further industrial applications.Herein,we designed and synthesized asymmetric non-fused electron-deficient building block TIC-Br with a simple structure(only three synthetic steps),showing a planar configuration,excellent electron affinity,and large dipole moment.A simple polymer acceptor PTIB was further developed by polymerization of TIC-Br and sensitized fluorinated-thienyl benzodithiophene(BDT-TF-Sn).PTIB exhibits a broad absorption from 300 to 800 nm,a suitable lowest unoccupied molecular orbital(LUMO) energy level of-3.86 e V,and moderate electron mobility(1.02×10^(-4)cm^(2)V^(-1)s^(-1)).When matched with PM6,the device achieved the best PCE of 10.11%with a high V_(OC) of 0.97 V,which is one of the highest among those reported all-PSCs.More importantly,PTIB exhibits a lower synthetic complexity index(SC=35.0%)and higher figure-of-merit values(FOM=29.0%) than all the reported high-performance PAs.The polymer also exhibits excellent batch-to-batch reproducibility and great potential for scale-up fabrication.This study indicates that TIC-Br is a promising building block for constructing low-cost polymer acceptors for large-scale applications in all-PSCs.

Low-cost polymer acceptors with noncovalently fused-ring backbones for efficient all-polymer solar cells

The polymerization of fused-ring acceptors(FRAs) to afford their corresponding polymeric acceptors for high-performance all-polymer solar cells(all-PSCs) has achieved remarkable progress in the past few years.However,due to the high degree of synthetic complexity for the monomer,the high-cost of these polymeric acceptors may limit their commercial applications.Thus,it is urgent to develop inexpensive and high-performance polymeric acceptors for all-PSCs.Herein,two novel polymeric acceptors(PBTzO and PBTzO-2F) have been designed and synthesized by copolymerization of noncovalently fused ring acceptors(NFRAs),which were employed in all-PSCs for the first time.Upon introducing the “noncovalently conformational locks(NoCLs)” in the backbone and selective fluorination of the end-group,photophysical and electrical properties,and solidstate packing properties of the NFRAs have been rationally tuned.As a result,the PBDB-T:PBTzO-2F based devices presented an excellent power conversion efficiency(PCE) of 11.04%,much higher than that of PBTzO based ones due to the increased charge generation and extraction,improved hole transfer and carrier mobilities,and reduced energy loss.More importantly,PBTzO-2F exhibited a much lower synthetic complexity(SC) index and higher figure-of-merit(FOM) values than the high-performance fused-ring acceptor based polymer acceptors(FRA-PAs) due to the simpler structures and more effective synthesis.This contribution provided a novel idea to achieve low-cost and high-performance all-PSCs.

Organic small molecule acceptor materials for organic solar cells

The active layer of organic solar cells(OSCs)is composed of a p-type conjugated polymer as the donor and an ntype organic semiconductor as the acceptor.Since the report of bulk-heterojunction OSCs with soluble C60 derivative PCBM as the acceptor in 1995,fullerene derivatives,including PCBM and the C70 derivative PC71BM,have been the dominant acceptors in OSCs for 20 years.In 2015,the A–D–A structured small molecule acceptor(SMA)was developed,which possesses the advantages of a narrow bandgap,strong absorption in the long wavelength region,and suitable electronic energy levels,in contrast to the fullerene derivative acceptors.A–D–A SMAs boost the power conversion efficiency(PCE)of OSCs to the 10–14%level.Recently,benefiting from the innovation of A–DA0D–A structured SMAs,the PCE of OSCs has rapidly increased from 15%to 19%.In this review,the development history of n-type organic semiconductor acceptor materials is briefly introduced.The molecular structures and the physicochemical and photovoltaic properties of acceptors,including fullerene derivatives and narrow bandgap SMAs,are described.In particular,the effect of regulating the molecular packing and miscibility of SMAs on their photovoltaic performance is discussed.Finally,current challenges and prospects for n-type organic semiconductor acceptors are analyzed and discussed.

硅半导体太阳能电池进展

太阳能电池是将太阳能直接转化为电能的装置,也是有效利用太阳能最佳途径之一。作为一种绿色能源,尤其是在核电安全问题面临挑战的今天,太阳能电池被认为是解决能源衰竭和环境污染等一系列重大问题的最佳选择。目前,许多国家正在制订中长期太阳能开发计划,准备在21世纪大规模开发太阳能。当前研究最多同时在生产应用的最广泛的当数硅太阳能电池(如单晶硅、多晶硅、非晶硅等)。通过对各类硅太阳能电池的性能、工艺、转化效率以及制备方法等方面作比较并讨论了它们各自性能的优劣,最后结合当前国内外工业化生产状况,对硅太阳能电池研究现状和各自的最新进展作了比较详细的综述,并简要讨论了硅太阳能电池研究和生产上的前景及趋势。

太阳能电池及多晶硅的生产

在简述太阳能电池原理和发展的基础上,分析了太阳能电池用多晶硅的生产方法.认为:改良的熔盐电解法和熔盐三层电解精炼法有可能直接制取太阳能级多晶硅,此法一旦研究成功,将大幅度地降低太阳能级多晶硅生产成本,应引起人们的关注.

用开路电压法测硅太阳电池中少数载流子寿命

太阳电池基区的少数载流子寿命是影响电池效率的重要因素之一。开路电压衰减法 (OCVD)具有直接、简单、重复性好等特点 ,可准确测量器件的少数载流子寿命。该文分别介绍了利用纳秒激光器和发光二极管 (LED)作为OCVD的光源 ,测量晶体硅太阳电池的少子寿命 ,结果发现可以利用脉冲信号发生器带动发光二极管作为脉冲光源 ,取代纳秒激光器 。

a-Si:H薄膜的再结晶技术及Si膜的Raman光谱分析

论述了非晶硅薄膜的几种主要再结晶技术 ,着重指出了各种晶化技术已取得的研究成果、优缺点、有待进一步研究的内容及其在多晶硅薄膜太阳电池工业生产中的应用前景。另外 ,还讨论了通过Raman光谱求纳晶硅薄膜的晶粒尺寸和结晶度的方法。

多晶硅片表面缺陷的研究与定向凝固多晶硅锭热场模拟

结合实际工艺模拟多晶硅铸锭生产过程中的热场分布情况,研究了该热场对所生产多晶硅片缺陷分布的影响。同时采用对多晶硅片化学腐蚀抛光处理和位错刻蚀液处理之后的表面缺陷形貌表征的方法,以及观察扫描电镜(SEM)视角下其表面微结构,研究了采用定向凝固多晶硅锭工艺所得的多晶硅片表面缺陷情况。结果显示模拟该生产过程中热场分布情况对多晶硅片缺陷的影响和实验所得的结果相吻合。

空间电荷区和晶界复合对多晶太阳电池基区少数载流子寿命的影响

该文采用多晶硅太阳电池模型,通过引入空间电荷区复合速度来研究空间电荷区复合对少子寿命的影响,从计算结果中发现当复合速率大于105cm/s时,空间电荷区的复合影响不可忽略,必须对所测得的寿命值进行修正。

硅基单结太阳能电池的制备技术、缺陷及其性能的研究

首先综述了硅基单结太阳能电池的分类、制备方法及进展,介绍了化学气相沉积法、液相外延法(LPPE)、金属诱导结晶法(MIC)、磁控溅射法以及分子束外延法等各种硅基太阳能电池的制备方法,阐述了各种制备工艺的优缺点。其次,总结了单晶硅、多晶硅以及非晶硅太阳能电池在组织结构、缺陷方面的研究现状。最后,对硅基太阳能电池的机械、电学、光学以及光电性能等方面的研究进展做了论述。

低成本多晶硅太阳电池性能的模拟

提出低成本太阳能级多晶硅太阳电池的一维模型,多晶硅材料是由物理冶金法提纯的。在接近实际的条件下,计算了晶粒大小和晶界复合速率对电池光电转换效率的影响。模拟结果与实验数据基本吻合。实验和模拟结果表明要使电池性能达到最佳,晶粒尺寸需大于5mm;晶界复合速率足够低的情况下,对晶粒尺寸的要求可降低。

多晶硅铸锭炉生产工艺控制技术和设备组成

多晶硅铸锭炉是多晶硅制造的关键设备之一,其工艺流程的稳定性、设备控制的稳定性和先进性直接关系到是否生成出合格的硅锭,而合格的硅锭直接决定着硅片制成的电池的光电转换效率。比较详细地介绍了多晶硅铸锭炉典型的生产工艺、设备组成和控制系统。重点介绍了控制系统的硬件控制结构、软件流程以及在设计时体现出的独到的设计理念和创新性。

上海世博会主题馆光伏发电系统

上海世博会主题馆30000m2光伏建筑一体化光伏发电系统,设计发电功率为2.5MW,年发电量250万kWh。介绍其设计理念;屋面太阳能电池的选择、布置;变配电系统的构成;防雷与接地系统的实际做法等。

多晶硅太阳电池材料的光致发光理论和实验研究

报道了多晶硅太阳电池材料的光致发光理论和实验研究结果。给出了多晶硅样品光致发光相对强度的二维扫描记录和晶粒边界附近相对发光强度及相差变化的实验曲线。

酸腐蚀多晶硅表面的光反射率计算

分析了现有酸腐蚀多晶硅表面光反射率计算模型中存在的基本问题,提出了更符合酸腐蚀多晶硅表面形貌特征的光反射率计算模型,并就波长为550nm的单色光垂直照射下的光反射率随表面凹坑深度与球体半径比值H_(max)/R的变化进行了系统计算。结果表明,当H_(max)/R在0～0.29之间时是完全一次反射区,R_(total)是一恒定值。随着H_(max)/R增加,反射次数增多,反射率下降。当H_(max)/R=1时,也就是凹坑深度刚好为球半径时,反射率最低。