高效聚合物和硫化铅胶体量子点太阳电池及其光电性能的研究
发布时间：2018-08-22 17:11
【摘要】：从太阳光中直接获取能量的光伏技术被认为是最有潜力解决能源危机的方法之一。尽管传统无机太阳电池已经取得了巨大的进步和发展，但原材料价格昂贵和生产成本较高限制了其大规模应用。近年来，以聚合物太阳电池和胶体量子点太阳电池为代表的新型太阳电池技术引起了学术界和工业界的广泛关注。通过改变聚合物材料的分子结构，能够调节材料的带隙和载流子迁移率等参数，使得聚合物太阳电池的材料选择范围更加广泛。通过改变量子点的尺寸、形状、组分和聚集形态可以对其电学和光学性质进行调节，使得胶体量子点太阳电池能够吸收利用太阳光谱中的可见光和红外光。这两种新型太阳电池技术同时都具备溶液加工、制备工艺简单、低成本和可制备大面积柔性器件等优点，已经成为光电材料与器件领域的研究热点。目前溶液加工的聚合物太阳电池和胶体量子点太阳电池的最高能量转换效率分别达到了10.6%和7.4%，但距离实际应用仍然有一段距离。本博士学位论文的工作主要包括基于低温溶液加工方式制备的高效率柔性聚合物太阳电池和PbS胶体量子点太阳电池及其光电性能研究，同时研究了溶剂处理方法对聚合物太阳电池的活性层形貌和光伏性能的影响，为采用溶液加工方式制备低成本的新型太阳电池技术提供有价值的参考。 在第一部分工作中，我们采用倒置器件结构，获得了能量转换效率为8.71%的高效柔性聚合物太阳电池，器件的短路电流达到17.9mA cm-2，开路电压达到0.74V，填充因子为65.9%。这一结果得到了国家光伏质检中心的独立认证，是目前文献公开报道的最高效率。研究发现，醇溶性聚合物聚[(9,9-二(3’-(N,N-二甲基胺)丙基)-2,7-芴)-alt-2,7-(9,9-二辛基芴)](PFN)可以降低聚对苯二甲酸乙二醇酯衬底氧化铟锡(PET/ITO)的表面粗糙度和功函数，使得ITO与活性层之间形成利于电子输运的欧姆接触，有利于载流子的收集。这种高效柔性聚合物太阳电池的稳定性同样优异，器件在空气中放置120天，能量转换效率仍能维持初始效率的92%。在弯曲条件下测试，器件的光伏性能并没有发生明显的衰减。上述优异的性能为柔性聚合物太阳的实际应用打下良好基础。柔性聚合物太阳电池的理论质量功率可达到400W Kg-1，大大高于基于单晶硅的电池模组的功率密度，，而与最好性能的薄膜电池相媲美。这一优点使得这种电池有望在便携电源和空间卫星等领域得到应用。低温溶液加工是这种高效聚合物太阳电池的最突出优点，器件在制备过程中没有采用任何的热处理工艺，为在室温条件下高效大面积柔性聚合物太阳电池的工业化生产提供了一种参考方法。 聚合物太阳电池的光伏性能与活性层的形貌密切相关。在第二部分工作中，我们采用溶剂退火的处理方法对活性层的形貌进行优化，提高了聚合物太阳的光伏性能，并探讨了其作用机理。对于基于P3HT/PCBM体系的聚合物太阳电池，结合这一优化和使用ZnO/PFN作为阴极修饰层，器件的能量转换效率达到了4.53%。在此基础上，以溶液加工的V2O5代替蒸镀的MoO3作为空穴抽取层材料，制备了能量转换效率为3.66%的全溶液加工P3HT/PCBM体系聚合物太阳电池。我们同时考察了低沸点溶剂退火对基于D-A型窄带隙聚合物电子给体材料的太阳电池的影响，我们认为低沸点溶剂退火能够诱导活性层中给体、受体相发生相分离，从而优化活性层形貌，增强薄膜光吸收和载流子迁移率。能量转换效率的提高主要来源于填充因子的贡献。这种低沸点溶剂退火方法具有一定的通用性，活性层薄膜经低沸点溶剂处理过程之后，PDTBDTFTQ/PC71BM体系聚合物太阳电池的能量转换效率从5.21%提高到7.25%，填充因子从49.9%提高到74.1%。SFTBT/PC71BM体系有机小分子太阳电池的能量转换效率从1.88%提高到3.39%。PCDTBT/PC71BM体系聚合物太阳电池的能量转换效率从5.16%提高到7.03%。研究结果表明，低沸点溶剂退火的处理时间对器件的光伏性能有重大影响，溶剂退火时间过长容易引起给/受体相分离程度过度扩大，增大了载流子复合的概率，从而降低了器件的短路电流和能量转换效率。 在第三部分工作中，我们采用有机/无机复合配体钝化方法，获得了分散性良好、尺寸均匀的硫化铅(PbS)量子点，制备了高效率的肖特基结构PbS胶体量子点太阳电池。器件的开路电压和能量转换效率分别为0.54V和3.72%。论文讨论了复合配体中不同烷基链长度的有机配体对PbS胶体量子点的尺寸、分散性、晶体结构和吸收光谱的影响。我们研究了不同烷基链长度的保护溶剂对PbS胶体量子点太阳电池光伏性能的影响，烷基链较长的油胺制备的PbS肖特基太阳电池性能最优，能量转换效率达到3.52%。研究还表明，在PbS胶体量子点太阳电池中引入醇溶性聚合物材料PFN作为阴极界面修饰层，可有效降低器件的漏电流，并提高器件的填充因子和能量转换效率。
[Abstract]:Photovoltaic technology is considered as one of the most promising solutions to the energy crisis. Although traditional inorganic solar cells have made tremendous progress and development, their large-scale applications have been limited by the high cost of raw materials and production. Point solar cells have attracted much attention in academia and industry. By changing the molecular structure of polymer materials, the band gap and carrier mobility of polymer materials can be adjusted, so that the material selection range of polymer solar cells can be wider. Composition and aggregation morphology can be used to adjust their electrical and optical properties, so that colloidal quantum dot solar cells can absorb and utilize visible and infrared light in the solar spectrum. At present, the maximum energy conversion efficiency of polymer solar cells and colloidal quantum dot solar cells processed by solution is 10.6% and 7.4% respectively, but it is still a long way from practical application. High-efficiency flexible polymer solar cells and PBS colloidal quantum dots solar cells and their photoelectric properties were studied. The effect of solvent treatment on the morphology of active layer and photovoltaic properties of polymer solar cells was also studied.
In the first part of the work, we used inverted device structure to obtain high efficiency flexible polymer solar cells with energy conversion efficiency of 8.71%. The short-circuit current of the solar cells reached 17.9 mA cm-2, the open-circuit voltage reached 0.74 V, and the filling factor was 65.9%. This result has been independently certified by the National Photovoltaic Quality Inspection Center and is now published in the literature. It was found that the surface roughness and work function of poly (9,9-bis(3'-(N,N-dimethylamine) propyl) - 2,7-fluorene) - alt-2,7-(9,9-dioctylfluorene)] (PFN) on polyethylene terephthalate (PET/ITO) substrate could be reduced by the alcohol-soluble polymer, resulting in the formation of an Ohmic junction between ITO and the active layer, which is conducive to electron transport. The high-efficiency flexible polymer solar cell also has excellent stability. The energy conversion efficiency of the device can still maintain 92% of the initial efficiency after 120 days in the air. The photovoltaic performance of the device has not been significantly attenuated under bending conditions. The theoretical mass power of flexible polymer solar cells can reach 400W Kg-1, which is much higher than the power density of single crystal silicon based solar cell modules, and is comparable to the best performance thin film solar cells. This advantage makes this kind of solar cells hopeful to be used in portable power sources and space satellites. Liquid processing is the most prominent advantage of this kind of high-efficiency polymer solar cell. No heat treatment process is used in the preparation of the device, which provides a reference method for the industrial production of high-efficiency large-area flexible polymer solar cells at room temperature.
The photovoltaic performance of polymer solar cells is closely related to the morphology of the active layer. In the second part, we optimize the morphology of the active layer by solvent annealing, improve the photovoltaic performance of polymer solar cells, and explore its mechanism. An energy conversion efficiency of 4.53% was achieved by optimizing and using ZnO/PFN as the cathode modification layer. On this basis, the polymer solar cells with energy conversion efficiency of 3.66% were prepared by using V2O5 processed in solution instead of MoO3 evaporated as the hole extraction layer. The influence of annealing agent on D-A type narrow band gap polymer electron donor solar cells is discussed. We believe that low boiling point solvent annealing can induce donor and acceptor phase separation in the active layer, thus optimizing the morphology of the active layer, enhancing the optical absorption and carrier mobility of the films. The energy conversion efficiency of PDTBDTFTQ/PC71BM polymer solar cells increased from 5.21% to 7.25%, and the filling factor increased from 49.9% to 74.1%. The energy conversion of SFTBT/PC71BM organic small molecule solar cells was also improved. The energy conversion efficiency of PCDTBT/PC71BM polymer solar cells increased from 5.16% to 7.03%. The results show that the treatment time of low boiling point solvent annealing has a significant effect on the photovoltaic performance of the devices. The long annealing time of the solvents tends to cause excessive separation of donor/acceptor phase and increase the load. The probability of current recombination reduces the short circuit current and energy conversion efficiency of the device.
In the third part of the work, we used the organic/inorganic complex ligand passivation method to obtain well-dispersed lead sulfide (PbS) quantum dots with uniform size. High-efficiency Schottky structure PbS colloidal quantum dot solar cells were prepared. The open-circuit voltage and energy conversion efficiency of the devices were 0.54V and 3.72% respectively. The effects of organic ligands with different alkyl chain lengths on the size, dispersion, crystal structure and absorption spectra of PbS colloidal quantum dots were investigated. The effects of protective solvents with different alkyl chain lengths on the photovoltaic performance of PbS colloidal quantum dots solar cells were investigated. The conversion efficiency is 3.52%. The study also shows that the introduction of alcohol-soluble polymer PFN as cathode interface modification layer in PbS colloidal quantum dot solar cells can effectively reduce the leakage current of the device, and improve the filling factor and energy conversion efficiency.
【学位授予单位】：华南理工大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TM914.4
本文编号：2197774
[Abstract]:Photovoltaic technology is considered as one of the most promising solutions to the energy crisis. Although traditional inorganic solar cells have made tremendous progress and development, their large-scale applications have been limited by the high cost of raw materials and production. Point solar cells have attracted much attention in academia and industry. By changing the molecular structure of polymer materials, the band gap and carrier mobility of polymer materials can be adjusted, so that the material selection range of polymer solar cells can be wider. Composition and aggregation morphology can be used to adjust their electrical and optical properties, so that colloidal quantum dot solar cells can absorb and utilize visible and infrared light in the solar spectrum. At present, the maximum energy conversion efficiency of polymer solar cells and colloidal quantum dot solar cells processed by solution is 10.6% and 7.4% respectively, but it is still a long way from practical application. High-efficiency flexible polymer solar cells and PBS colloidal quantum dots solar cells and their photoelectric properties were studied. The effect of solvent treatment on the morphology of active layer and photovoltaic properties of polymer solar cells was also studied.
In the first part of the work, we used inverted device structure to obtain high efficiency flexible polymer solar cells with energy conversion efficiency of 8.71%. The short-circuit current of the solar cells reached 17.9 mA cm-2, the open-circuit voltage reached 0.74 V, and the filling factor was 65.9%. This result has been independently certified by the National Photovoltaic Quality Inspection Center and is now published in the literature. It was found that the surface roughness and work function of poly (9,9-bis(3'-(N,N-dimethylamine) propyl) - 2,7-fluorene) - alt-2,7-(9,9-dioctylfluorene)] (PFN) on polyethylene terephthalate (PET/ITO) substrate could be reduced by the alcohol-soluble polymer, resulting in the formation of an Ohmic junction between ITO and the active layer, which is conducive to electron transport. The high-efficiency flexible polymer solar cell also has excellent stability. The energy conversion efficiency of the device can still maintain 92% of the initial efficiency after 120 days in the air. The photovoltaic performance of the device has not been significantly attenuated under bending conditions. The theoretical mass power of flexible polymer solar cells can reach 400W Kg-1, which is much higher than the power density of single crystal silicon based solar cell modules, and is comparable to the best performance thin film solar cells. This advantage makes this kind of solar cells hopeful to be used in portable power sources and space satellites. Liquid processing is the most prominent advantage of this kind of high-efficiency polymer solar cell. No heat treatment process is used in the preparation of the device, which provides a reference method for the industrial production of high-efficiency large-area flexible polymer solar cells at room temperature.
The photovoltaic performance of polymer solar cells is closely related to the morphology of the active layer. In the second part, we optimize the morphology of the active layer by solvent annealing, improve the photovoltaic performance of polymer solar cells, and explore its mechanism. An energy conversion efficiency of 4.53% was achieved by optimizing and using ZnO/PFN as the cathode modification layer. On this basis, the polymer solar cells with energy conversion efficiency of 3.66% were prepared by using V2O5 processed in solution instead of MoO3 evaporated as the hole extraction layer. The influence of annealing agent on D-A type narrow band gap polymer electron donor solar cells is discussed. We believe that low boiling point solvent annealing can induce donor and acceptor phase separation in the active layer, thus optimizing the morphology of the active layer, enhancing the optical absorption and carrier mobility of the films. The energy conversion efficiency of PDTBDTFTQ/PC71BM polymer solar cells increased from 5.21% to 7.25%, and the filling factor increased from 49.9% to 74.1%. The energy conversion of SFTBT/PC71BM organic small molecule solar cells was also improved. The energy conversion efficiency of PCDTBT/PC71BM polymer solar cells increased from 5.16% to 7.03%. The results show that the treatment time of low boiling point solvent annealing has a significant effect on the photovoltaic performance of the devices. The long annealing time of the solvents tends to cause excessive separation of donor/acceptor phase and increase the load. The probability of current recombination reduces the short circuit current and energy conversion efficiency of the device.
In the third part of the work, we used the organic/inorganic complex ligand passivation method to obtain well-dispersed lead sulfide (PbS) quantum dots with uniform size. High-efficiency Schottky structure PbS colloidal quantum dot solar cells were prepared. The open-circuit voltage and energy conversion efficiency of the devices were 0.54V and 3.72% respectively. The effects of organic ligands with different alkyl chain lengths on the size, dispersion, crystal structure and absorption spectra of PbS colloidal quantum dots were investigated. The effects of protective solvents with different alkyl chain lengths on the photovoltaic performance of PbS colloidal quantum dots solar cells were investigated. The conversion efficiency is 3.52%. The study also shows that the introduction of alcohol-soluble polymer PFN as cathode interface modification layer in PbS colloidal quantum dot solar cells can effectively reduce the leakage current of the device, and improve the filling factor and energy conversion efficiency.
【学位授予单位】：华南理工大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TM914.4
【参考文献】
相关博士学位论文 前3条
1 杨庭斌;新型结构聚合物太阳电池与光探测器的制备及其性能研究[D];华南理工大学;2012年
2 何志才;基于电极界面层调控实现电池高效聚合物太阳池的研究[D];华南理工大学;2013年
3 汪青;界面修饰聚合物电致发光器件及其物理机制研究[D];华南理工大学;2013年
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