Charge Transport in Disordered Organic Materials and Its Relevance to Thin‐Film Devices: A Tutorial Review

Semiconducting polymers and small molecules form an extremely flexible class of amorphous materials that can be used in a wide range of applications, some of which are display, radio-frequency tags, and solar cells. The rapid progress towards functional devices is occurring despite the lack of sufficient understanding of the physical processes and very little experience in device engineering. This tutorial review aims to provide sufficient intuitive background to draw more researchers to look into the fundamental aspects of device physics and engineering.

[1]  Richard H. Friend,et al.  Pulsed excitation of low-mobility light-emitting diodes: Implication for organic lasers , 1999 .

[2]  B. Shklovskii,et al.  Effective temperature of hopping electrons in a strong electric field. , 1992, Physical review. B, Condensed matter.

[3]  P. Blom,et al.  Unified description of charge-carrier mobilities in disordered semiconducting polymers. , 2005, Physical review letters.

[4]  Electronic Properties of Organic Thin Films Studied by Kelvin Probe Force Microscopy , 2006 .

[5]  Vladimir Arkhipov,et al.  Charge injection into light-emitting diodes: Theory and experiment , 1998 .

[6]  M. Lampert,et al.  Current injection in solids , 1970 .

[7]  N. Tessler,et al.  Carrier heating in disordered organic semiconductors , 2006 .

[8]  Charles E. Swenberg,et al.  Electronic Processes in Organic Crystals , 1982 .

[9]  K. Maeda.  Gaussian distribution of inhomogeneous barrier height in Si Schottky barriers , 2001 .

[10]  R. Friend,et al.  Analysis of the turn-off dynamics in polymer light-emitting diodes , 2000 .

[11]  I. P. Zvyagin,et al.  Percolation Approach to Hopping Transport in Organic Disordered Solids , 2002 .

[12]  V. Arkhipov,et al.  Non-Langevin recombination in disordered materials with random potential distributions , 1997 .

[13]  M. Kemerink,et al.  Three-dimensional inhomogeneities in PEDOT:PSS Films , 2004 .

[14]  Richard H. Friend,et al.  Transient electroluminescence of polymer light emitting diodes using electrical pulses , 1999 .

[15]  S. Novikov,et al.  Dipole-trap model and non-dispersive charge-carrier transport in polymers of various structures , 1994 .

[16]  Noam Rappaport,et al.  The mobility spatial distribution function: Turn-on dynamics of polymer photocells , 2006 .

[17]  Esther M. Conwell,et al.  High-field hopping mobility in molecular systems with spatially correlated energetic disorder , 1995 .

[18]  V. Sa-yakanit,et al.  Analytic expression for electronic density of states in random media with weak scattering potential , 2008 .

[19]  Paul Ernest Parris,et al.  Essential Role of Correlations in Governing Charge Transport in Disordered Organic Materials , 1998 .

[20]  Antonio Cerdeira,et al.  New procedure for the extraction of a-Si:H TFTs model parameters in the subthreshold region , 2003 .

[21]  H. Bässler.  Charge Transport in Disordered Organic Photoconductors a Monte Carlo Simulation Study , 1993 .

[22]  E. I. Levin,et al.  Hopping Photoconductivity in Amorphous Semiconductors: Dependence on Temperature, Electric Field and Frequency , 1990 .

[23]  Richard L. Martin,et al.  Molecular geometry fluctuations and field-dependent mobility in conjugated polymers , 2001 .

[24]  Robert A. Street,et al.  Technology and Applications of Amorphous Silicon , 2000 .

[25]  Glatz,et al.  Hole mobilities in films of a pyrazoline:polycarbonate molecularly doped polymer. , 1990, Physical review. B, Condensed matter.

[26]  Measurements of the Einstein relation in doped and undoped molecular thin films , 2008 .

[27]  T. Holstein,et al.  Studies of polaron motion: Part II. The “small” polaron , 1959 .

[28]  James C. Sturm,et al.  Thermal effects and scaling in organic light-emitting flat-panel displays , 1998 .

[29]  D. Vanmaekelbergh,et al.  Wide energy-window view on the density of states and hole mobility in poly(p-phenylene vinylene). , 2004, Physical review letters.

[30]  Jürgen H. Werner,et al.  Barrier inhomogeneities at Schottky contacts , 1991 .

[31]  Priya J. Jadhav,et al.  Electric-field-dependent percolation model of charge-carrier mobility in amorphous organic semiconductors , 2007 .

[32]  G. Horowitz,et al.  Extracting Parameters from the Current–Voltage Characteristics of Organic Field‐Effect Transistors , 2004 .

[33]  Franco Cacialli,et al.  Indium-tin oxide treatments for single- and double-layer polymeric light-emitting diodes: The relation between the anode physical, chemical, and morphological properties and the device performance , 1998 .

[34]  Hsieh,et al.  Exciton formation and decay dynamics in electroluminescent polymers observed by subpicosecond stimulated emission. , 1994, Physical review. B, Condensed matter.

[35]  C. Chan,et al.  Direct determination of the hole density of states in undoped and doped amorphous organic films with high lateral resolution. , 2005, Physical review letters.

[36]  P. Borsenberger,et al.  Hole trapping in molecularly doped polymers , 1997 .

[37]  N. Tessler,et al.  Spatially dispersive transport: A mesoscopic phenomenon in disordered organic semiconductors , 2007 .

[38]  Y. Shirota,et al.  Negative electric-field dependence of hole drift mobility for a molecular glass of tri(o-terphenyl-4-yl)amine , 1997 .

[39]  Y. Eichen,et al.  Charge Density and Film Morphology Dependence of Charge Mobility in Polymer Field‐Effect Transistors , 2003 .

[40]  P. Heremans,et al.  Effect of doping on the density-of-states distribution and carrier hopping in disordered organic semiconductors , 2005 .

[41]  H. Bässler,et al.  Disorder in Charge Transport in Doped Polymers , 1994 .

[42]  Michael F. Shlesinger,et al.  Time‐Scale Invariance in Transport and Relaxation , 1991 .

[43]  H. Bässler,et al.  CURRENT INJECTION FROM A METAL TO A DISORDERED HOPPING SYSTEM. II. COMPARISON BETWEEN ANALYTIC THEORY AND SIMULATION , 1999 .

[44]  Monroe,et al.  Hopping exponential band tails. , 1985, Physical review letters.

[45]  D. Goldie.  The effect of spatial disorder on the mobility of charge carriers hopping through energetically disordered dipolar lattices , 2000 .

[46]  Nir Tessler,et al.  Generalized Einstein relation for disordered semiconductors—implications for device performance , 2002 .

[47]  R. Friend,et al.  The use of electrical pulses to study the physics of bilayer organic light-emitting diodes , 2005 .

[48]  Michael S. Shur,et al.  Physics of amorphous silicon based alloy field‐effect transistors , 1984 .

[49]  Nevill Mott,et al.  The theory of impurity conduction , 1961 .

[50]  Y. Rosenwaks,et al.  Electronic properties of doped molecular thin films measured by Kelvin probe force microscopy. , 2006, The journal of physical chemistry. B.

[51]  N. Tessler,et al.  Analysis and modeling of organic devices , 2004 .

[52]  Janos Veres,et al.  Low‐k Insulators as the Choice of Dielectrics in Organic Field‐Effect Transistors , 2003 .

[53]  M. Sampietro,et al.  Dependence of the mobility on charge carrier density and electric field in poly(3-hexylthiophene) based thin film transistors : Effect of the molecular weight , 2008 .

[54]  N. Mott,et al.  Electronic Processes In Non-Crystalline Materials , 1940 .

[55]  Andrew G. Glen,et al.  APPL , 2001 .

[56]  R. Gurney,et al.  Electronic Processes in Ionic Crystals , 1964 .

[57]  N. Tessler,et al.  Amorphous organic molecule/polymer diodes and transistors—Comparison between predictions based on Gaussian or exponential density of states , 2005 .

[58]  P. Anderson.  Absence of Diffusion in Certain Random Lattices , 1958 .

[59]  Paul Davids,et al.  Device model investigation of bilayer organic light emitting diodes , 2000 .

[60]  M. Michels,et al.  Understanding the doping dependence of the conductivity of conjugated polymers: Dominant role of the increasing density of states and growing delocalization , 2003 .

[61]  N. T. Harrison,et al.  CURRENT HEATING IN POLYMER LIGHT EMITTING DIODES , 1998 .

[62]  Daniel F. Blossey,et al.  One-dimensional Onsager theory for carrier injection in metal-insulator systems , 1974 .

[63]  Nir Tessler,et al.  Self-consistent analysis of the contact phenomena in low-mobility semiconductors , 2003 .

[64]  George G. Malliaras,et al.  Charge injection and recombination at the metal–organic interface , 1999 .

[65]  E. Abrahams,et al.  Impurity Conduction at Low Concentrations , 1960 .

[66]  E. Montroll,et al.  Anomalous transit-time dispersion in amorphous solids , 1975 .

[67]  Xiaoyuan Hou,et al.  Carrier density dependence of mobility in organic solids: A Monte Carlo simulation , 2007 .

[68]  Benjie Limketkai,et al.  Charge Injection into Cathode-Doped Amorphous Organic Semiconductors , 2005 .

[69]  Vinay Ambegaokar,et al.  Hopping Conductivity in Disordered Systems , 1971 .

[70]  M. Vissenberg,et al.  Theory of the field-effect mobility in amorphous organic transistors , 1998, cond-mat/9802133.

[71]  John Ziman,et al.  Models of disorder , 1979 .

[72]  R. Friend,et al.  Analysis of polymer-based devices , 2001 .

[73]  S. Guha,et al.  Temperature dependent photoluminescence of organic semiconductors with varying backbone conformation , 2003 .

[74]  H. Bässler,et al.  Concerning the role of dipolar disorder on charge transport in molecularly doped polymers , 1991 .

[75]  Scher,et al.  Transition from dispersive to nondispersive transport: Photoconduction of polyvinylcarbarzole. , 1987, Physical review. B, Condensed matter.

[76]  P. Heremans,et al.  Weak-field carrier hopping in disordered organic semiconductors: the effects of deep traps and partly filled density-of-states distribution , 2002 .