LEADER 00000nam  2200361   4500 
001    AAI3161907 
005    20051108101749.5 
008    051108s2005                        eng d 
020    0496954490 
035    (UnM)AAI3161907 
040    UnM|cUnM 
100 1  Xue, Jiangeng 
245 10 Pure and mixed organic thin films and heterojunctions for 
       optoelectronic applications 
300    323 p 
500    Source: Dissertation Abstracts International, Volume: 66-
       01, Section: B, page: 0469 
500    Adviser:  Stephen R. Forrest 
502    Thesis (Ph.D.)--Princeton University, 2005 
520    Molecular organic thin films have been used as active 
       materials in organic light-emitting devices (OLEDs), 
       photovoltaic cells, photodetectors, and thin-film 
       transistors. In this thesis, we study the properties of 
       pure and mixed organic thin films and various 
       heterojunction (HJ) structures, and their influences on 
       the performance of organic optoelectronic devices 
520    In Part I, we study the thin film growth of a planar-
       stacking molecule, BTQBT. Charge transport in BTQBT films 
       is revealed by studying the field-effect mobility of thin-
       film transistors using such films as the channel. Mixing 
       BTQBT with another molecule, PTCDA, leads to enhanced 
       electrical conductivity, and the unique "bipolar doping" 
       between the organic donor-acceptor (D-A) couple is 
       demonstrated 
520    Part II is devoted to multilayer organic photodetectors 
       with an alternating donor and acceptor layers as the 
       active region. We study the carrier transport within the 
       multilayer D-A HJ as well as at its contact with the 
       anode. Charge carriers tunneling through the thin (≤30A
       thick) individual active layers are responsible for the 
       high quantum efficiency and bandwidth of these devices, 
       whereas thermally-assisted tunneling injection of 
       electrons from the anode into the organic layers dominates
       the dark current. Furthermore, optical bistability is 
       achieved when such a photodetector is integrated on top of
       an OLED, extending the functionality of this type of 
       device 
520    Organic photovoltaic cells have the potential for low-cost
       solar energy conversion, and are studied in Part III. We 
       demonstrate that cells with very low series resistances 
       can be fabricated, and their performance can be described 
       using conventional p-n junction theory. The photovoltaic 
       characteristics of various D-A HJ structures are studied, 
       including a planar HJ between pure layers, a mixed HJ with
       donor and acceptor molecules mixed on the molecular scale,
       and a hybrid planar-mixed HJ (PM-HJ) with a mixed layer 
       sandwiched between pure layers. A power conversion 
       efficiency of 5.0% under 1 sun (simulated AM1.5) is 
       demonstrated in a CuPC-C60 hybrid PM-HJ cell, which is 
       further improved to a record-high 5.7% by stacking two 
       thin hybrid PM-HJ cells in series 
590    School code: 0181 
590    DDC 
650  4 Engineering, Electronics and Electrical 
650  4 Engineering, Materials Science 
690    0544 
690    0794 
710 20 Princeton University 
773 0  |tDissertation Abstracts International|g66-01B 
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