Delayed Luminescence Spectroscopy of Organic Photovoltaic Binary Blend Films: Probing the Emissive Non‐geminate Charge Recombination
Delayed Luminescence Spectroscopy of Organic Photovoltaic Binary Blend Films: Probing the Emissive Non‐geminate Charge Recombination
复制标题
有机光伏二元共混薄膜的延迟发光光谱：探测发射性非双生电荷复合
DOI：
10.1002/adma.201002389
复制
发表时间：
2010
影响因子：
29.4
通讯作者：
J. Nelson
中科院分区：
文献类型：
--
作者：
P. E. Keivanidis;V. B. Kamm;C. Dyer-Smith;W. Zhang;F. Laquai;I. McCulloch;D. D. C. Bradley;J. Nelson
利用二元有机复合材料是低成本有机光伏(OPV)器件新兴技术的一个关键方面。[1]OPV器件的光活性层是电子供体(p型)和电子接受体(n型)的固态混合物，通常被称为体异质结。[2]OPV中的电荷产生机制包括光诱导电子转移(PET)反应[3]和电荷转移(CT)态的产生，[4]涉及给体和受主成分。在CT状态分离成自由电荷之后，通过在器件电极处收集自由载流子来产生光电流。[5]众所周知，在OPV器件中，主要的光电流损失途径是通过静电结合的电荷载体的复合，即所谓的双酸盐复合事件。然而，完全分离的电荷载体也可能在与最初发生PET反应的位置空间不同的位置处重新结合。由这些非双原子复合事件引起的光电流损失的重要性正变得越来越明显。[11-13]本文提出延迟发光(DL)光谱[14，15]可以作为监测OPV复合材料中发射非双原子电荷复合损失的合适光谱技术。本文给出了N，N‘-双(1-乙基丙基)-3，4，9，10-戊二酰二亚胺(PDI)与聚(9，9’-二辛基荧烷-苯并噻二唑)(F8BT)或聚(9，9’-dioctylindenofluorene-co-benzothiadiazole)(PIF8BT).)共混膜的时间积分和时间分辨光谱结果[13，16，17]PIF8BT是一种新型吲哚共聚物，与F8BT共混制得的光伏器件具有较高的光电压和较大的光电流，是一种很有前途的受主候选材料。在这两种聚合物：PDI共混膜中，我们同时使用F8BT和PIF8BT作为施主材料。特别是，我们从光谱上研究了在每种情况下，在PDI和聚合物之间形成的CT态发射的强度和动力学。以分散在无定形聚苯乙烯(PS)中的PDI共混膜为参照系。图1a显示了PDI、PIF8BT和F8BT的化学结构。对于F8BT：PdI太阳电池，非双态电荷复合事件已被确定为主要的光电流损失。[13]由于我们的时间门控检测窗口扩展到ms时间范围，将讨论CT发射与双分子非双态电荷复合之间的可能关系。我们的结论得到了在μS时间范围内对F8BT：PdI系统器件进行的电场诱导DL猝灭实验的支持。图1b展示了原始的PIF8BT薄膜的UV-Vis和PL光谱。还给出了PS：PdI和PIF8BT：PdI薄膜的UV-Vis光谱。对于F8BT和PIF8BT薄膜，吸收光谱和荧光光谱的低能部分是相似的(参见辅助信息)。PIF8BT发射光谱与PDI吸收光谱的重叠表明，当激发该体系的PIF8BT成分时，将发生Förster共振能量转移(FRET)。这种行为以前在F8BT：PDI共混膜中观察到。[17]图1c显示了PS：PDI、F8BT：PDI和PIF8BT：PDI共混膜在420 nm激发波长下的光致发光光谱(聚合物本身主要吸收)。在F8BT：PdI系统的光致发光中不存在F8BT在540 nm区域的特征光致发光特征，而在该区域的PIF8BT的光谱特征特征可以是…
The utilization of binary organic composites is a key aspect of the emerging technology of low-cost organic photovoltaic (OPV) devices.[1] The photoactive layers of OPV devices are solid state mixtures of electron donating (p-type) and electron accepting (n-type) components that are best known as bulk heterojunctions.[2] The scheme of charge generation in OPVs involves a photo-induced electron transfer (PET) reaction [3] and the generation of a charge transfer (CT) state,[4] involving the donor and the acceptor components. Following the separation of the CT state into free charges, photocurrent generation occurs through free carrier collection at the device electrodes.[5] It is well documented that a major photocurrent loss pathway in OPV devices is through recombination of the electrostatically bound charge carriers, so-called geminate recombination events.[6–10] However, fully separated charge carriers may also recombine at sites that are spatially different than the sites where the PET reaction has initially taken place. The significance of photocurrent losses due to these non-geminate recombination events is becoming increasingly apparent.[11–13] This paper proposes that delayed luminescence (DL) spectroscopy [14, 15] can be utilized as an appropriate spectroscopic technique for monitoring emissive non-geminate charge recombination losses in OPV composites. Here we present time-integrated and time-resolved spectroscopic results for blend films of N, N’-bis (1-ethylpropyl)-3, 4, 9, 10-perylene tetracarboxy diimide)(PDI) when mixed with poly (9, 9’-dioctylfluorene-co-benzothiadiazole)(F8BT) or poly (9, 9’-dioctylindenofluorene-co-benzothiadiazole)(PIF8BT). PDI is a promising acceptor candidate material and when blended with F8BT it delivers OPV devices with high photovoltage and relatively high photocurrent.[13, 16, 17] PIF8BT is a new indenofluorene copolymer. In both polymer: PDI blend films we use both F8BT and PIF8BT as donor materials. In particular we investigate spectroscopically the strength and the dynamics of emission from the CT state formed between the PDI and the polymer in each case. As a reference system, blend films of PDI dispersed in amorphous poly (styrene)(PS) are used. The chemical structures of PDI, PIF8BT and F8BT are shown in Figure 1a. For solar cells of F8BT: PDI, non-geminate charge recombination events have been identified as the dominant photocurrent loss.[13] Since our time-gated detection window extends into the ms time range, the possible relationship between CT emission and bimolecular non-geminate charge recombination will be addressed. Our conclusions are supported by electricfield induced DL quenching experiments performed in the μs time range for devices of the F8BT: PDI system. Figure 1 b presents the UV-Vis and PL spectra of a pristine PIF8BT film. The UV-Vis spectra of the PS: PDI and of the PIF8BT: PDI films are also shown. For films of both F8BT and PIF8BT the low energy part of the absorption spectra and the PL spectra are similar (see Supporting Information). The spectral overlap of the PIF8BT emission with the PDI absorption suggests that Förster resonant energy transfer (FRET) will occur upon excitation of the PIF8BT component of this system. Such a behaviour was observed previously in F8BT: PDI blend films.[17] Figure 1 c presents the PL spectra of the PS: PDI, F8BT: PDI and PIF8BT: PDI blend films at the excitation wavelength of 420 nm (where the polymers alone mainly absorb). The characteristic PL signature of F8BT in the region of 540 nm is not present in the PL of the F8BT: PDI system whereas the spectral signature of the PIF8BT in this region can be …
登录
查看更多内容
聚（对亚苯基亚乙烯基）衍生物的延迟荧光：三重态-三重态湮灭与双对重组
DOI：
--
发表时间：
2002
期刊：
影响因子：
--
作者：
A. Gerhard;H. Bässler
通讯作者：
H. Bässler
影响因子：
3.7
作者：
C. Dyer‐Smith;Jessica J. Benson-Smith;D. Bradley;H. Murata;W. Mitchell;S. Shaheen;S. Haque;J. Nelson
通讯作者：
C. Dyer‐Smith;Jessica J. Benson-Smith;D. Bradley;H. Murata;W. Mitchell;S. Shaheen;S. Haque;J. Nelson
影响因子：
4
作者：
Deibel, C.;Baumann, A.;Dyakonov, V.
通讯作者：
Dyakonov, V.
Langmuir-Blodgett 薄膜中苝二聚体的发光和构型
DOI：
10.1021/j100058a029
发表时间：
1994
期刊：
The Journal of Physical Chemistry
影响因子：
--
作者：
J. Mahrt;F. Willig;W. Storck;D. Weiss;R. Kietzmann;K. Schwarzburg;B. Tufts;B. Troesken
通讯作者：
B. Troesken
共轭聚合物中的双子对重组
DOI：
--
发表时间：
1999
期刊：
影响因子：
--
作者：
B. Schweitzer;V. Arkhipov;U. Scherf;H. Bässler
通讯作者：
H. Bässler