電荷傳輸基團改質發光高分子電荷傳遞機制與聚噻吩本質電荷遷移率之研究

劉景洋

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電荷傳輸基團改質發光高分子電荷傳遞機制與聚噻吩本質電荷遷移率之研究

Studies on Charge Transport Mechanism in Electroluminescent Polymers Containing Charge Transport Moieties and Intrinsic Charge Mobilty in Poly(3-hexylthiophene)

劉景洋 , Ph.D　　Advisor：陳壽安　　

繁體中文

電荷傳遞；電荷陷阱；高分子發光二極體；電荷遷移率；電荷傳輸基團； charge transport ； charge trap ； polymer light-emitting diode ； charge mobility ； charge transport moiety

Abstract │ Reference (169) │ Altmetrics

Abstract 〈TOP〉

本研究的目的為探討發光高分子側鏈以電荷傳輸基團改質後的電荷傳遷機制以及量測聚噻吩之本質電荷遷移率。首先以spiropolyfluorene(sPF)與polycarbazole(PCzB)經過不同的電荷傳輸基團改質後所得到的TPAsPF、G-sPF、PCzBOXD及PCzBCz四種系統作為研究對象，利用飛行時間法、熱激發電流、單一載子電流特性的量測，並結合電荷傳遞模型Gaussian Disorder Model (GDM)、Correlated Disorder Model (CDM)及Gill model分析，了解改質後材料的電荷傳遞機制以及電荷注入行為。最後，藉由量測poly(3-alkylthiophene) (P3HT) 在摻雜前後微波導電度的變化，計算出P3HT的本質電荷遷移率。
    在TPAsPF與G-sPF系統中， TPA與Cz相對於主鏈分別為0.4與0.2 eV的電洞陷阱，由時間飛行法(Time-of-flight, TOF)可觀察到電洞的移動會受到TPA與Cz基團的限制，使得電洞遷移電流由未改質前的非分散型(non-dispersive)轉變成分散型(dispersive)。sPF具有很高的電洞遷移率10-3 cm2/Vs，經GDM與Gill model的分析可得到其傳遞系統的能量亂度(σsPF)與躍遷活化能(Ea, sPF)分別為84 meV與283 meV。在50 %側鏈基團比例時，無論是TPA50-sPF或是50 G-sPF其電洞遷移率都下降三個數量級至4×10-6 cm2/Vs，且其能量亂度與電洞躍遷活化能也都大幅地增加(σTPA50-sPF: 128 meV, σ50 G-sPF : 125 meV, Ea,TPA50-sPF : 622 meV, Ea, 50 G-sPF: 576 meV)。隨著側鏈基團比例增加，局部區域的側鏈基團會形成電洞通道，加速電洞的傳遞，因此，TPA100-sPF與100 G-sPF的電洞遷移率也分別上升至10-4 cm2/Vs與10-5 cm2/Vs，其能量亂度與電洞躍遷活化能也會跟著降低。由熱激發電流量測結果可證明TPA基團為電洞陷阱的來源，其陷阱釋放機制是由側鏈的熱運動帶動了側鏈基團上陷阱電荷的釋放，若在sPF與TPA之間，加入了Cz基團，使得sPF、Cz與TPA基團對於電洞形成階梯式的能階，此設計增加了電洞在三者之間躍遷的機率以及降低側鏈基團的陷阱效應，故在G-sPF系統所能觀察到的陷阱電流值僅為TPAsPF系統的5.5%。對於電洞注入方面，Spiropolyfluorene的側鏈導入TPA基團後，可提升電洞的注入量超過6000倍，若以TPA-Cz所組成的階梯式能階改質後，更可提升電洞的注入量達70000倍。
    在PCzBOXD與PCzBCz系統中，OXD與Cz的氧化電位分別高於主鏈PCzB主鏈1.2與0.3 eV，因此OXD與Cz基團在此二系統中扮演電洞阻擋的角色。未改質的PCzB具有非分散型的電洞遷移電流，其電洞遷移率為10-5 cm2/Vs。導入OXD與Cz基團後，電洞遷移電流會轉變為分散型，表示改質後的材料不利於電洞的傳遞，其電洞遷移率隨著OXD與Cz基團的比例增加而逐漸降低。經由GDM與Gill model的分析，PCzBOXD與PCzBCz系統的能量亂度與電洞躍遷活化能並不會隨OXD與Cz基團的比例增加而有明顯地改變。CDM傳遞模型分析指出，電洞在此二系統中平均傳遞的距離會隨著側鏈基團的比例增加而變大，並且傳遞距離與主鏈的體積分率具有相似的相依性，綜合以上的資訊，我們認為電洞在此二系統中是經由主鏈傳遞，主要的傳遞過程由主鏈間的傳遞(inter-chain transport)所主導。對於電荷注入而言，Polycarbazole導入具有電洞阻擋與電子傳輸性質的OXD基團後，可抑制電洞的注入至原來的2.4%，並提升電子的注入量達200倍以上。然而在PCzBCz系統中，導入的Cz基團對於電子與電洞的注入影響就不明顯。
    我們以化學摻雜取代time-resolved microwave conductivity (TRMC)中以雷射或電子束作為激發光源產生載子的方式，在P3HT溶液中形成可移動的偏極子(polaron)。此外，產生載子的數目可由摻雜濃度準確地計算出來。P3HT溶液配製成0.1 mg/ml，其摻雜濃度的範圍介於0 ~ 3%，隨著摻雜濃度的提高，P3HT溶液吸收微波的強度也會增加，代表導電度的變化會隨摻雜濃度的提高而增加。但計算所得到的電洞遷移率卻由0.1% 摻雜濃度的0.032 cm2/Vs降低至3% 摻雜濃度的0.0064 cm2/Vs，其下降的原因可解釋為：(1)提高摻雜濃度後，高分子鏈上的偏極子與counter ion的數目變多，增加了高分子鏈間的庫侖吸引力，且摻雜後的P3HT的高分子鏈的構形會趨向rod-like性質，使得P3HT鏈容易形成聚集，增加偏極子進行inter-chain transport的機率，而降低電洞遷移率。(2)在高摻雜濃度之下，平均一條高分子鏈上形成不只一個偏極子，偏極子之間的庫侖排斥力會使得載子移動的速度減低。在0.1 %的摻雜濃度下，高分子鏈沒有聚集以及庫侖排斥力影響，偏極子可自由地在P3HT上移動，此時P3HT的一維電洞遷移率(μ1D)達0.1 cm2/Vs可視為P3HT的本質電洞遷移率。

Parallel Abstract 〈TOP〉

The aims of this study are (1) to understand charge transport mechanism in electroluminescent polymers grafted with charge transport moieties and (2) to evaluate the intrinsic charge mobility of poly(3-hexylthiophene) (P3HT). Four model systems based on spiropolyfluorene (sPF) and polycarbazole (PCzB) grafted with different charge transport moieties, including TPAsPF, G-sPF, PCzBOXD, and PCzBCz, are investigated. By uses of time-of-flight (TOF), thermally stimulated current (TSC), single carrier current characteristics measurement, together with analyses based on Gaussian Disorder Model (GDM), Correlated Disorder Model (CDM), and Gill model, we have proposed charge transport mechanisms and charge injection behaviors for these materials. We also demonstrate a facile method to evaluate the intrinsic charge mobility of poly(3-alkylthiophene) (P3HT) by measuring the change of microwave conductivity of P3HT in solution after doping.
    In spiropolyfluorene grafted with TPA moieties (termed as TPAsPF) and gradient-ionization-potential TPA-Cz moieties (termed as G-sPF), both TPA and Cz act as hole traps relative to the main chain (sPF) with trap depths of 0.4 and 0.2 eV, respectively. From the results of TOF measurements, hole current transient will be changed from a non-dispersive type in sPF to a dispersive type in the modified sPF, indicating hole transport is severely limited by the incorporation of TPA and Cz moieties. sPF exhibits a high hole mobility of 10-3 cm2/Vs and its energetic disorder and hopping activation energy extracted from GDM and Gill model are determined as 84 and 283 meV, respectively. Incorporating with 50 % side chain moieties, both TPA50-sPF and 50 G-sPF reduce their hole mobilities to 4×10-6 cm2/Vs, three orders of magnitude less than that of sPF, leading to an increase in their energetic disorder and hopping activation (σTPA50-sPF: 128 meV, σ50 G-sPF : 125 meV, Ea,TPA50-sPF : 622 meV, Ea, 50 G-sPF: 576 meV). Further increase in the content of side chain moieties, TPA and Cz will form hole channels to facilitate hole transport. Therefore, hole mobilities of TPA100-sPF and 100 G-sPF are enhanced to 10-4 and 10-5 cm2/Vs, respectively. And their energetic disorder and hopping activation are also reduced. The results of TSC measurements evidence that trapping current observed in TSC spectra is originated from TPA moieties. The detrapping mechanism can be considered as that thermal motion of side chain triggers the release of charges trapped by side chain moieties. In G-sPF system, a gradient ionization potential formed by TPA, Cz, and sPF can increase the probability of hopping among these three species and alleviate the trapping effect of side chain moieties. Only 5.5% trapping current in TPAsPF can be observed in G-sPF system. The incorporation of TPA moieties can promote hole injection exceeding more than 6,000 times. And the incorporation of gradient-ionization-potential TPA-Cz moieties can further improve hole injection by more than 70, 000 times.
    In polycarbazole grafted with OXD moieties (termed as PCzBOXD) and Cz moieties (termed as PCzBCz), both OXD and Cz serve as hole-blocking moieties relative to the main chain (PCzB) with barriers of 1.2 and 0.3 eV, respectively. Without modification, PCzB shows a non-dispersive hole transport and its hole mobility reaches 10-5 cm2/Vs. Dispersive current transients are observed in polycarbazole containing OXD and Cz moieties, indicating that the incorporation of OXD and Cz moieties brings a negative effect on hole transport. Their hole mobilities gradually decrease with increasing the content of side chain moieties. From the analyses of TOF results with GDM and Gill model, the energetic disorder and hopping activation energy vary little with the content of side chain moieties. The CDM analysis indicates that the average hopping distance will increase with increasing the content of OXD and Cz moieties. And these two systems hold a similar dependence on the relationship between hopping distance and volume ratio of main chain. Combining all information above, we conclude that inter-chain charge hopping dominates hole transport process. For charge injections, the presence of OXD moieties, which owns its hole-blocking and electron-transporting characteristics, can reduce hole injection ratio to only 2% and promote electron injection ratio by a factor of 200. However, the effect of Cz moieties on both electron and hole injection is not obvious in PCzBCz system.
    For measuring intrinsic hole mobility in P3HT, instead of using a laser or an electron accelerator as excitation sources in time-resolved microwave conductivity (TRMC) measurement, we generate moving charge carriers (polarons) of P3HT in its solutions by adding chemical dopants. The number of generated charge carriers can be accurately estimated from the doping level. P3HT solutions were prepared as 0.1 mg/ml with the doping level from 0 to 3%. The amount of microwave power absorbed by P3HT solutions will increase with increasing the doping levels, representing that the conductivity change increases with the doping levels. However, the deduced hole mobility decreases from 0.032 to 0.0064 cm2/Vs as the doping level increases from 0.1 to 3 %. The reasons are given as follows. The first, as the doping level increases, more and more polarons and counter ions are generated in P3HT chains, leading to stronger attractive forces between P3HT chains. And the conformation of doped P3HT exhibit rod-like characteristics, which favors P3HT chains to segregate together. The formation of segregation increases the probability of inter-chain transport and decreases hole mobility. The second, on average, more than one polarons per chain are generated in the high doping level greater than 0.3%. Coulombic repulsive force between moving polarons within a chain also reduce the moving capability of polarons. At the lowest doping level of 0.1%, the absence of P3HT segregation and coulombic repulsive force allows polarons moving freely along isolated P3HT chains. In this case, the deduced one-dimensional hole mobility (μ1D) of P3HT reaches 0.1 cm2/Vs, which can be considered as the intrinsic hole mobility of P3HT.

Reference ( 169 ) 〈TOP〉

[1] 1. J. C. W. Chien, “Polyacetylene:Chemistry, Physics, and Material Science”, Academic Press, Orlando, 1984.
連結：
[9] C. Kittel, “Introduction to Solid State Physics”, 6th edition, John Wiley & Son, Singapore, 1986.
連結：
[13] R. A. Wessling, J. Polymer. Sci., Polym. Symp. 1985, 72, 55.
連結：
[14] D. Braun and A. J. Heeger, Appl. Phys. Lett. 1991, 58, 1982.
連結：
[16] M. Fukuda, K. Sawada, and K. Yoshino, Jpn. J. Appl. Phys. 1989, 28, L1433.
連結：

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