Analysis of negative capacitance and self-heating in organic semiconductor devices

In admittance spectroscopy of organic semiconductor devices, negative capacitance values arise at low frequency and high voltages. This study aims at explaining the influence of self-heating on the frequency-dependent capacitance and demonstrates its impact on steady-state and dynamic experiments. Therefore, a one dimensional numerical drift-diffusion model extended by the heat equation is presented. We calculate the admittance with two approaches: a Fourier method that is applied to time domain data and a numerically efficient sinusoidal steady state analysis (S3A), which is based on the linearization of the equations around the operating point. The simulation results coincide well with the experimental findings from reference [H. Okumoto and T. Tsutsui, Appl. Phys. Express 7, 061601 (2014)] where the negative capacitance effect of an organic device becomes weaker with better cooling of the structure. Linking the frequency- and time-domain with the Fourier approach supports an effortless interpretation o...

[1]  Stephan Harkema,et al.  Large area ITO-free flexible white OLEDs with Orgacon PEDOT:PSS and printed metal shunting lines , 2009, Organic Photonics + Electronics.

[2]  Juan Bisquert,et al.  Impedance of carrier injection at the metal-organic interface mediated by surface states in electron-only tris(8-hydroxyquinoline) aluminium (Alq 3 ) thin layers , 2008 .

[3]  B. Ruhstaller,et al.  Numerical analysis of steady-state and transient charge transport in organic semiconductor devices , 2010, Numerical Simulation of Optoelectronic Devices.

[4]  P. Blom,et al.  Simultaneous measurement of electron and hole mobilities in polymer light-emitting diodes , 2000 .

[5]  Oleg Sergiyenko.  Optoelectronic Devices and Properties , 2011 .

[6]  T. Tansley,et al.  An instrumental solution to the phenomenon of negative capacitances in semiconductors , 1996 .

[7]  Beat Ruhstaller,et al.  Numerical impedance analysis for organic semiconductors with exponential distribution of localized states , 2011 .

[8]  Karl Leo,et al.  Feel the Heat: Nonlinear Electrothermal Feedback in Organic LEDs , 2013 .

[9]  M. Hersam,et al.  Negative capacitance in organic light-emitting diodes , 2005 .

[10]  G. Wright,et al.  Characteristics of the space-charge-limited dielectric diode at very high frequencies , 1961 .

[11]  Beat Ruhstaller,et al.  The role of shallow traps in dynamic characterization of organic semiconductor devices , 2012 .

[12]  Tetsuo Tsutsui,et al.  A source of negative capacitance in organic electronic devices observed by impedance spectroscopy: Self-heating effects , 2014 .

[13]  N. S. Sariciftci,et al.  Negative capacitance in organic semiconductor devices: Bipolar injection and charge recombination mechanism , 2007, 0706.3933.

[14]  Juan Bisquert,et al.  Kinetics of interface state-limited hole injection in α-naphthylphenylbiphenyl diamine (α-NPD) thin layers , 2009 .

[15]  M. Buchanan,et al.  Negative capacitance effect in semiconductor devices , 1998 .

[16]  Stephen R. Forrest,et al.  Thermal analysis of high intensity organic light-emitting diodes based on a transmission matrix approach , 2011 .

[17]  Beat Ruhstaller,et al.  Numerical simulation of charge transport in disordered organic semiconductor devices , 2010 .

[18]  X. Hou,et al.  Negative capacitance in doped bi-layer organic light-emitting devices , 2011 .

[19]  Michael Heuken,et al.  Electrothermal characterization of large-area organic light-emitting diodes employing finite-element simulation , 2011 .

[20]  Martijn Kemerink,et al.  Negative capacitances in low-mobility solids , 2005 .

[21]  H. Kwok.  Modeling negative capacitance effect in organic polymers , 2003 .

[22]  Jongwoon Park,et al.  Large-area OLED lightings and their applications , 2011 .

[23]  A. Many,et al.  Theory of Transient Space-Charge-Limited Currents in Solids in the Presence of Trapping , 1962 .