裁剪型有机光伏小分子及其衍生物的研究与应用#

有机太阳能电池光电转化效率已经突破13%,这主要归因于活性层材料的不断丰富与改进。其中,以聚合物为母体的裁剪型分子,其相比于聚合物具有明确的分子量,共轭长度可调,高消光系数,优良的结晶性等优势。本文简要介绍裁剪型分子在二元本体异质结体系,三元体系,非富勒烯体系中的应用及我们组的相关研究工作,总结了其特点并对其应用前景做了展望。     

Polycyclic Aromatic Hydrocarbons as Potential Building Blocks for Organic Solar Cells

Since the discovery of graphene in the early 2000′s, polycyclic aromatic hydrocarbons (PAHs) have been resurrected and new synthetic tools have been developed to prepare unprecedented structures with unique properties. One application that has been overlooked for this class of molecules is organic solar cells (OSCs). In this account, we present the recent development in the preparation of moderate to low band gap PAHs that could potentially be used as semiconducting materials in OSCs. Our focus is directed toward all‐carbon PAHs as well as their polymeric analogs.     

Recent structural evolution of lactam- and imide-functionalized polymers applied in organic field-effect transistors and organic solar cells

Organic semiconductor materials, especially donor–acceptor (D–A) polymers, have been increasingly applied in organic optoelectronic devices, such as organic field-effect transistors (OFETs) and organic solar cells (OSCs). Plenty of high-performance OFETs and OSCs have been achieved based on varieties of structurally modified D–A polymers. As the basic building block of D–A polymers, acceptor moieties have drawn much attention. Among the numerous types, lactam- and imide-functionalized electron-deficient building blocks have been widely investigated. In this review, the structural evolution of lactam- or imide-containing acceptors (for instance, diketopyrrolopyrrole, isoindigo, naphthalene diimide, and perylene diimide) is covered and their representative polymers applied in OFETs and OSCs are also discussed, with a focus on the effect of varied structurally modified acceptor moieties on the physicochemical and photoelectrical properties of polymers. Additionally, this review discusses the current issues that need to be settled down and the further development of new types of acceptors. It is hoped that this review could help design new electron-deficient building blocks, find a more valid method to modify already reported acceptor units, and achieve high-performance semiconductor materials eventually.

This review highlights the recent structural evolution of lactam- and imide-functionalized polymers applied in organic field-effect transistors and organic solar cells.     

Development of New Two‐Dimensional Small Molecules Based on Benzodifuran for Efficient Organic Solar Cells

A new organic small molecule, DCA3TBDF, with a 2D benzo[1,2‐b:4,5‐b′]difuran (BDF) moiety as the central core and octyl cyanoacetate units as the end‐capped blocks, was designed and synthesized for solution‐processed bulk heterojunction solar cells. DCA3TBDF possesses good solubility in common organic solvents such as toluene, CH₂Cl₂, chlorobenzene, and CHCl₃ and good thermal stability with an onset decomposition temperature with 5 % weight‐loss occurring at 361 °C. The DCA3TBDF thin film showed a broad absorption at λ=320–700 nm and high crystallinity. Small‐molecule organic solar cells based on DCA3TBDF and [6,6]‐phenyl‐C₆₁‐butyric acid methyl ester demonstrated promising power conversion efficiency with a high fill factor under the illumination of AM 1.5G (100 mW cm^?2).     

Effective design of A-D-A small molecules for high performance organic solar cells via F atom substitution and thiophene bridge

Novel A-D-A-type small molecule donors employ thiophene bridge and F-substitution to improve the power conversion efficiency in organic solar cell.     

A‐D‐A Type Small Molecules Based on Boron Dipyrromethene for Solution‐Processed Organic Solar Cells

The unique properties of boron dipyrromethene (BODIPY) dyes including facile synthesis, high absorption coefficients, and delocalized molecular orbitals as well as excellent photochemical and thermal stability, make them promising as materials for organic solar cells. Accordingly, in this study three A‐D ‐A structural small molecules of BDTT‐BODIPY, FL‐BODIPY, and TT‐BODIPY have been synthesized, in which two BODIPY acceptor units are symmetrically conjugated to 4,8‐bis(5‐(2‐ethylhexyl) thiophen‐2‐yl)benzo[1,2‐b:4,5‐b]dithiophene (BDTT), 9,9‐dioctyl‐9H‐fluorene (FL), and thieno[3,2‐b]thiophene (TT) donor cores, respectively. The manipulation of the structural parameters significantly improves the performances of the BHJ OSCs, which show power conversion efficiencies of 4.75 %, 1.51 %, and 1.67 % based on [6,6]‐phenyl C₇₁‐butyric acid methyl ester (PC₇₁BM) as the acceptor material and BDTT‐BODIPY, FL‐BODIPY, and TT‐BODIPY as the donor materials, respectively.     

Thieno[3,4‐c]pyrrole‐4,6‐dione‐Based Small Molecules for Highly Efficient Solution‐Processed Organic Solar Cells

Two small molecules named BT‐TPD and TBDT‐TTPD with a thieno[3,4‐c]pyrrole‐4,6‐dione (TPD) unit were designed and synthesized for solution‐processed bulk‐heterojunction solar cells. Their thermal, electrochemical, optical, charge‐transport, and photovoltaic characteristics were investigated. These compounds exhibit strong absorption at 460–560 nm and low highest occupied molecular orbital levels (?5.36 eV). Field‐effect hole mobilities of these compounds are 1.7–7.7×10^?3 cm² V^?1 s^?1. Small‐molecule organic solar cells based on blends of these donor molecules and a acceptor display power conversion efficiencies as high as 4.62 % under the illumination of AM 1.5G, 100 mW cm^?2.     

A–π–D–π–A Electron‐Donating Small Molecules for Solution‐Processed Organic Solar Cells: A Review

Organic solar cells based on semiconducting polymers and small molecules have attracted considerable attention in the last two decades. Moreover, the power conversion efficiencies for solution‐processed solar cells containing A–π–D–π–A‐type small molecules and fullerenes have reached 11%. However, the method for designing high‐performance, photovoltaic small molecules still remains unclear. In this review, recent studies on A–π–D–π–A electron‐donating small molecules for organic solar cells are introduced. Moreover, the relationships between molecular properties and device performances are summarized, from which inspiration for the future design of high performance organic solar cells may be obtained.     

New D-π-A dyes for efficient dye-sensitized solar cells

Functional organic dyes have promising prospect in dye-sensitized solar cells as a crucial element, of which sensitizers based on donor-π-acceptor are the most important dyes. On the basis of the structures of the aromatic amine donors such as triphenylamine and indoline, this paper reviews the photoelectric conversion properties of organic sensitizers since 2008, and highlights research work in our laboratory in this area.     

新型D-π-A类敏化太阳电池染料及其应用

功能性有机染料在染料敏化太阳能电池领域具有重要的应用前景,电子给体、π共轭桥和电子受体（D-π-A）结构的染料是其中重要的组成类型.本文主要依据三苯胺和吲哚啉等取代苯胺为电子给体染料的结构设计,并结合本课题组的相关工作,综述了2008年以来此类D-π-A光敏染料的光电转换性能的研究进展.     

Recent advances of organometallic complexes in emerging photovoltaics

Organometallic complexes (OMCs) consisting of organic and metal active moieties have shown immense potential for application in solar cells. The diverse structure, rich porosity, and unique charge centers of OMCs enable them to be functional in solar cells. In this review, we introduced four types of OMCs, such as crown organometallic complexes, β-diketone metal complexes, cyclometallic complexes, and main chain metal-containing polymers, providing an in-depth analysis of the structure-performance relationship. OMCs could serve as active or interlayer materials in a variety of solar cell systems such as organic solar cells, perovskite solar cells, and dye-sensitized solar cells, especially some metals to improve the photoelectric performance of the device as dopants. In the end, perspectives on the opportunities and challenges of OMCs are given.     

Potential of Nonfullerene Small Molecules with High Photovoltaic Performance

Over the past decades, fullerene derivatives have become the most successful electron acceptors in organic solar cells (OSCs) and have achieved great progress, with power conversion efficiencies (PCEs) of over 11 %. However, fullerenes have some drawbacks, such as weak absorption, limited energy‐level tunability, and morphological instability. In addition, fullerene‐based OSCs usually suffer from large energy losses of over 0.7 eV, which limits further improvements in the PCE. Recently, nonfullerene small molecules have emerged as promising electron acceptors in OSCs. Their highly tunable absorption spectra and molecular energy levels have enabled fine optimization of the resulting devices, and the highest PCE has surpassed 12 %. Furthermore, several studies have shown that OSCs based on small‐molecule acceptors (SMA) have very efficient charge generation and transport efficiency at relatively low energy losses of below 0.6 eV, which suggests great potential for the further improvement of OSCs. In this focus review, we analyze the challenges and potential of SMA‐based OSCs and discuss molecular design strategies for highly efficient SMAs.     

Investigation of colloidal graphite as a matrix for matrix‐assisted laser desorption/ionisation mass spectrometry of low molecular weight analytes

The analysis of low molecular weight compounds by matrix‐assisted laser desorption/ionisation mass spectrometry is problematic due to the interference and suppression of analyte ionisation by the matrices typically employed – which are themselves low molecular weight compounds. The application of colloidal graphite is demonstrated here as an easy to use matrix that can promote the ionisation of a wide range of analytes including low molecular weight organic compounds, complex natural products and inorganic complexes. Analyte ionisation with colloidal graphite is compared with traditional organic matrices along with various other sources of graphite (e.g. graphite rods and charcoal pencils). Factors such as ease of application, spectra reproducibility, spot longevity, spot‐to‐spot reproducibility and spot homogeneity (through single spot imaging) are explored. For some analytes, considerable matrix suppression effects are observed resulting in spectra completely devoid of matrix ions. We also report the observation of radical molecular ions [M^–●] in the negative ion mode, particularly with some aromatic analytes. Copyright © 2016 John Wiley & Sons, Ltd.     

Phthalocyanine

Phthalocyanines, which have been produced for 75 years as blue and then as green pigments, are the most important organic colorants. Their mostly planar aromatic π‐system provides color‐fastness, ‐homogeneity, ‐intensity and ‐stability, combined with a simple synthetic access, which are prerequisites for its use as a colorant. In recent years, phthalocyanins have also found applications in CD/Rs, as blue and green colors in LCDs, as photoconductors in laser printers, and as p‐conductors and absorbers in organic solar cells. The system exhibits a great structural variability (different substituents at and metals/semimetals in the ligand) in order to tune different properties. Because of these presuppositions the phthalocyanines have a great potential for new applications also in other fields.     

无机材料在有机太阳能电池中的应用

无机材料电子迁移率高、光谱响应范围与太阳光谱匹配,而有机材料价格低廉、合成方法简单、容易制作在基底上,因此在太阳能电池中具有更广阔的应用前景。 目前,阻碍有机太阳能电池发展的主要原因是材料的载流子迁移率低、器件稳定性差、吸收光谱与太阳光谱不匹配,导致光电转换效率较低。 若能将有机、无机材料二者的优点相结合,将可提高有机太阳能电池的能量转换效率。 目前的研究已经取得了一定进展,无机材料在受体层、阴极缓冲层、阳极缓冲层中的应用均不同程度地提高了有机太阳能电池的能量转换效率。 本文综述了目前该领域的研究现状,并对今后的研究提出了展望。     

Electrocatalytic Recycling of CO2 and Small Organic Molecules

As global warming directly affects the ecosystems and humankind in the 21^st century, attention and efforts are continuously being made to reduce the emission of greenhouse gases, especially carbon dioxide (CO₂). In addition, there have been numerous efforts to electrochemically convert CO₂ gas to small organic molecules (SOMs) and vice versa. Herein, we highlight recent advances made in the electrocatalytic recycling of CO₂ and SOMs including (i) the overall trend of research activities made in this area, (ii) the relations between reduction conditions and products in the aqueous phase, (iii) the challenges in the use of gas diffusion electrodes for the continuous gas phase CO₂ reduction, as well as (iv) the development of state of the art hybrid techniques for industrial applications. Perspectives geared to fully exploit the potential of zero‐gap cells for CO₂ reduction in the gaseous phase and the high applicability on a large scale are also presented. We envision that the hybrid system for CO₂ reduction supported by sustainable solar, wind, and geothermal energies and waste heat will provide a long term reduction of greenhouse gas emissions and will allow for continued use of the abundant fossil fuels by industries and/or power plants but with zero emissions.     

Economical and Environmentally Friendly Organic hydrazone Derivatives Characterized by a Heteroaromatic Core as Potential Hole Transporting Materials in Perovskite Solar Cells

A series of organic electron-rich π-bridged symmetric hydrazones, composed of two donor moieties connected through a thiophene- or a pyrrole-based π-spacer, has been synthesized as a suitable alternative to 2,2’,7,7’-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9’-spirobifluorene ( Spiro-OMeTAD ), considered the benchmark hole transporting material (HTM) in perovskite solar cells (PSCs). The cheap synthetic protocol is suitable for potential large-scale production. All the compounds were characterized, showing good energy levels alignments with the perovskite and very close energy levels to the Spiro-OMeTAD . Furthermore, computational analysis confirmed the electrochemical trend observed. The costs of synthesis were estimated, as well as the produced waste to synthesise the final HTMs, underlining the low impact of these compounds on the environment with the respect to Spiro-OMeTAD . Overall, the relevant electrochemical properties and the low cost of the synthetic approaches allow these compounds to be a greener and easy-to-synthesize alternative to the Spiro-OMeTAD for industrial development of PSCs.     

有机太阳能电池材料研究新进展

介绍了有机太阳能电池研究的背景、基本原理、分类,并对有机太阳能电池材料进行了全面综述,包括小分子太阳能电池材料、大分子太阳能电池材料、D-A体系材料和有机无机杂化体系材料.     

New D-π-A-conjugated organic sensitizers based on α-pyranylidene donors for dye-sensitized solar cells

A series of new push-pull organic dyes incorporating a cyanoacrylic acid group as electron acceptor unit and α-chalcogenopyranylidene group (X = S; O) as electron donor unit has been synthesized, characterized and used as sensitizer for dye-sensitized solar cells (DSSCs). For the first time, α-pyranylidene and thiopyranylidene groups, have been evaluated in DSSC. To obtain the thermodynamic values of the solar cell, an investigation of their electrochemical (CV) and optical properties (UV–vis absorption spectroscopy) is also reported.     

基于非富勒烯小分子受体Y6的有机太阳能电池

随着给/受体材料的不断发展,有机太阳能电池的器件效率不断取得进展.特别是非富勒受体分子Y6的出现,使单结有机太阳能电池的效率突破了15％.Y6已经应用到了有机太阳能电池各个方面并且极大提升了其性能.本综述主要总结了Y6在二元、三元和四元、逐层印刷、柔性、叠层和半透明等有机太阳能电池方面的研究情况,以及基于Y6三线态的有...