Recombination in Quantum Dot Sensitized Solar Cells

被引:735
作者
Mora-Sero, Ivan [1 ]
Gimenez, Sixto [1 ]
Fabregat-Santiago, Francisco [1 ]
Gomez, Roberto [2 ,3 ]
Shen, Qing [4 ]
Toyoda, Taro [4 ]
Bisquert, Juan [1 ]
机构
[1] Univ Jaume 1, Dept Fis, Grp Dispositius Fotovolta & Optoelect, Castellon de La Plana 12071, Spain
[2] Univ Alacant, Dept Quim Fis, E-03080 Alicante, Spain
[3] Univ Alacant, Inst Univ Electroquim, E-03080 Alicante, Spain
[4] Univ Electrocommun, Dept Appl Phys & Chem, Tokyo 1828585, Japan
关键词
NANOSTRUCTURED TIO2 ELECTRODES; CARRIER DYNAMIC INVESTIGATIONS; IONIC-LAYER ADSORPTION; NANOCRYSTALLINE TIO2; OPTICAL-ABSORPTION; SURFACE-STATES; SEMICONDUCTOR NANOCRYSTALS; CHEMICAL CAPACITANCE; SOLUTION DEPOSITION; ENERGY CONVERSION;
D O I
10.1021/ar900134d
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
Quantum dot sensitized solar cells (QDSCs) have attracted significant attention as promising third-generation photovoltaic devices. In the form of quantum dots (QDs), the semiconductor sensitizers have very useful and often tunable properties; moreover, their theoretical thermodynamic efficiency might be as high as 44%, better than the original 31% calculated ceiling. Unfortunately, the practical performance of these devices still lags behind that of dye-sensitized solar cells. In this Account, we summarize the strategies for depositing CdSe quantum dots on nanostructured mesoporous TiO2 electrodes and discuss the methods that facilitate improvement in the performance and stability of QDSCs. One particularly significant factor for solar cells that use polysulfide electrolyte as the redox couple, which provides the best performance among QDSCs, is the passivation of the photoanode surface with a ZnS coating, which leads to a dramatic increase of photocurrents and efficiencies. However, these solar cells usually show a poor current-potential characteristic, so a general investigation of the recombination mechanisms is required for improvements. A physical model based on recombination through a monoenergetic TiO2 surface state that takes into account the effect of the surface coverage has been developed to better understand the recombination mechanisms of QDSCs. The three main methods of QD adsorption on TiO2 are (i) in situ growth of QDs by chemical bath deposition (CBD), (ii) deposition of presynthesized colloidal QDs by direct adsorption (DA), and (iii) deposition of presynthesized colloidal QDs by linker-assisted adsorption (LA). A systematic investigation by impedance spectroscopy of QDSCs prepared by these methods showed a decrease in the charge-transfer resistance and increased electron lifetimes for CBD samples; the same result was found after ZnS coating because of the covering of the TiO2 surface. The increase of the lifetime with the ZnS treatment has also been checked independently by open-circuit potential (V-OC) decay measurements. Despite the lower recombination rates by electron transfer to electrolyte as well as the higher light absorption of CBD samples, only a moderate increase of photocurrent compared with colloidal QD samples is obtained, indicating the presence of an additional, internal recombination pathway in the closely packed QD layer.
引用
收藏
页码:1848 / 1857
页数:10
相关论文
共 65 条
[1]   An electrochemical study on the nature of trap states in nanocrystalline rutile thin films [J].
Berger, Thomas ;
Lana-Villarreal, Teresa ;
Monllor-Satoca, Damian ;
Gomez, Roberto .
JOURNAL OF PHYSICAL CHEMISTRY C, 2007, 111 (27) :9936-9942
[2]   Determination of rate constants for charge transfer and the distribution of semiconductor and electrolyte electronic energy levels in dye-sensitized solar cells by open-circuit photovoltage decay method [J].
Bisquert, J ;
Zaban, A ;
Greenshtein, M ;
Mora-Seró, I .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 2004, 126 (41) :13550-13559
[3]   Chemical capacitance of nanostructured semiconductors: its origin and significance for nanocomposite solar cells [J].
Bisquert, J .
PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 2003, 5 (24) :5360-5364
[4]   The trap-limited diffusivity of electrons in nanoporous semiconductor networks permeated with a conductive phase [J].
Bisquert, J ;
Zaban, A .
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING, 2003, 77 (3-4) :507-514
[5]   Analysis of the mechanisms of electron recombination in nanoporous TiO2 dye-sensitized solar cells.: Nonequilibrium steady-state statistics and interfacial electron transfer via surface states [J].
Bisquert, J ;
Zaban, A ;
Salvador, P .
JOURNAL OF PHYSICAL CHEMISTRY B, 2002, 106 (34) :8774-8782
[6]   Analysis of the kinetics of ion intercalation - Ion trapping approach to solid-state relaxation processes [J].
Bisquert, J .
ELECTROCHIMICA ACTA, 2002, 47 (15) :2435-2449
[7]  
BISQUERT J, 2006, P SPIE INT SOC OPT E, V6192
[8]   A review of recent results on electrochemical determination of the density of electronic states of nanostructured metal-oxide semiconductors and organic hole conductors [J].
Bisquert, Juan ;
Fabregat-Santiago, Francisco ;
Mora-Sero, Ivan ;
Garcia-Belmonte, Germa ;
Barea, Eva M. ;
Palomares, Emilio .
INORGANICA CHIMICA ACTA, 2008, 361 (03) :684-698
[9]   Effect of energy disorder in interfacial kinetics of dye-sensitized solar cells with organic hole transport material [J].
Bisquert, Juan ;
Palomares, Emilio ;
Quinones, Cesar A. .
JOURNAL OF PHYSICAL CHEMISTRY B, 2006, 110 (39) :19406-19411
[10]   Spectroelectrochemical investigation of surface states in nanostructured TiO2 electrodes [J].
Boschloo, G ;
Fitzmaurice, D .
JOURNAL OF PHYSICAL CHEMISTRY B, 1999, 103 (12) :2228-2231