Hole transport parameters in a PTOPT based organic solar cell

2010 ◽  
Vol 88 (4) ◽  
pp. 253-256 ◽  
Author(s):  
Bizuneh Gebremichael ◽  
Genene Tessema
Keyword(s):  
Organic Solar Cell ◽  
Hole Transport ◽  
Zero Field ◽  
Transport Parameters ◽  
Limited Region ◽  
Electric Field Dependence ◽  
Pv Cell ◽  
Activation Factor ◽  
Field Mobility ◽  
Sandwich Type

The photovoltaic and charge transport properties of solar cells whose active layer is made from poly[3-(4-octylphenyl)-2, 2′-bithiophene](PTOPT) was studied. Devices are prepared in a sandwich-type structure of the form Al/PTOPT/PEDOT:PSS/ITO. The diodes showed good rectification needed for the PV cell. The symmetric nature of the semilogarithmic J–V plot under dark and low temperature reveals that there is a unipolar charge injection in both sides of the electrodes. Based on the space charge limited region J–V data, it was possible to study the electric field dependence of the hole transport, which enable us to derive important parameters such as the zero field mobility (μo) and the field activation factor (γ).

scholarly journals A Gated Four Probe Technique for Field Effect Measurements on Disordered Organic Semiconductors

2008 ◽  
Vol 63 (9) ◽  
pp. 591-595 ◽  
Author(s):  
Elizabeth von Hauff ◽  
Nicolas Spethmann ◽  
Jürgen Parisi
Keyword(s):  
Organic Semiconductors ◽  
Organic Semiconductor ◽  
Field Effect ◽  
Field Effect Transistors ◽  
Hole Transport ◽  
Organic Field Effect Transistors ◽  
Transport Parameters ◽  
Electric Field Dependence ◽  
High Impedance ◽  
Current Voltage

A gated four probe measurement technique to isolate contact resistances in field effect measurementson disordered organic semiconductors was investigated. Organic field effect transistors (OFETs) were prepared with two additional electrodes in the contact geometry protruding into the source-drain channel to monitor the variation in potential across the channel. Two high impedance electrometers were used to determine the potential at the contacts. This technique allows to directly determine the magnitude of the parasitic contact resistances between metal contact and organic semiconductor from the drop in potential at the contact regions. The effects of contact resistances, which can falsify measurements on bulk transport parameters such as the field effect mobility, can be then eliminated during material characterization. Additionally, the temperature and electric field dependence of the contact resistances offers valuable information about the charge injection and extraction processes between metal and organic semiconductor. The effects of the four probe geometry, specifically the effect of the channel electrodes on the current-voltage characteristics, of hole transport in a polythiophene (P3HT) OFET with Au contacts were investigated and found not to influence device performance, except at currents « 1 nA. The IV characteristics were shown to follow the expected FET behaviour. From the variation in potential along the channel it was found that contact resistances at the source contact (charge injecting contact) are minimal while contact resistances at thedrain contact (charge extracting contact) are significant, resulting in a much lower effective sourcedrain voltage than that applied to the device.

Characterization of Minority-Carrier Hole Transport in Nitride-Based Light-Emitting Diodes with Optical and Electrical Time-Resolved Techniques

2004 ◽  
Vol 831 ◽  
Author(s):  
R. J. Kaplar ◽  
S. R. Kurtz ◽  
D. D. Koleske ◽  
A. A. Allerman ◽  
A. J. Fischer ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Minority Carrier ◽  
Hole Transport ◽  
Optical Measurements ◽  
Hole Density ◽  
Transport Parameters ◽  
Two Phase ◽  
Time Resolved ◽  
Light Emitting ◽  
Order Of Magnitude

ABSTRACTForward-to-reverse bias step-recovery measurements were performed on In.07Ga.93N/GaN and Al.36Ga.64N/Al.46Ga.54N quantum-well (QW) light-emitting diodes grown on sapphire. With the QW sampling the minority-carrier hole density at a single position, distinctive two-phase optical decay curves were observed. Using diffusion equation solutions to self-consistently model both the electrical and optical responses, hole transport parameters τp = 758 ± 44 ns, Lp = 588 ± 45 nm, and μp = 0.18 ± 0.02 cm2/Vs were obtained for GaN. The mobility was thermally activated with an activation energy of 52 meV, suggesting trap-modulated transport. Optical measurements of sub-bandgap peaks exhibited slow responses approaching the bulk lifetime. For Al.46Ga.54N, a longer lifetime of τp = 3.0 μs was observed, and the diffusion length was shorter, Lp ≈ 280 nm. Mobility was an order of magnitude smaller than in GaN, μp ≈ 10−2 cm2/Vs, and was insensitive to temperature, suggesting hole transport through a network of defects.

Zero‐field mobility of excess electrons in dense methane gas

1977 ◽  
Vol 67 (10) ◽  
pp. 4636-4639 ◽  
Author(s):  
Ned E. Cipollini ◽  
Richard A. Holroyd ◽  
Masaru Nishikawa
Keyword(s):  
Zero Field ◽  
Methane Gas ◽  
Field Mobility ◽  
Excess Electrons

Electron recombination and diffusion in CO at elevated temperature

1969 ◽  
Vol 47 (17) ◽  
pp. 1789-1795 ◽  
Author(s):  
Michael H. Mentzoni ◽  
James Donohoe
Keyword(s):  
Room Temperature ◽  
Diagnostic Techniques ◽  
Zero Field ◽  
Time Decay ◽  
Electron Recombination ◽  
Average Temperature ◽  
Field Mobility ◽  
Ion Recombination ◽  
Pressure Interval ◽  
And Diffusion

The electron time decay in an afterglow following a short pulsed d.c. discharge in CO has been investigated using microwave diagnostic techniques. The gas was heated to an average temperature of 775 °K. Two-body electron-ion recombination and ambipolar diffusion were found to be the only important electron removal mechanisms present in the pressure interval [Formula: see text] Torr with the rate constants αr = 3.9 × 10−7 cm3 s−1 and Dap0 = 372 cm2 s−1 Torr respectively. If we postulate a T−γ dependence for αr, comparison with room temperature results yields γ = 0.57. The diffusion coefficient appears to increase strongly with temperature based upon an estimated zero field mobility for CO+in CO at 273 °K found in the literature.

Sign in / Sign up

Export Citation Format

Share Document