报告人：Giuseppe Baldacchini 教授
Via G. Quattrucci 246
00046 Grottaferrata, Roma, ITALY
Tel: +39-06-9410068 (mob. 333-6473768)
题目：The singular optical properties of Alq3 molecules and consequences on OLEDs
Organic light emitting devices, OLEDs, have been so much improved in the last two decades that they are being currently used in commercial applications for displays and lighting. Among many improving technologies, annealing processes affect greatly their performances, especially when the active material is the small molecule Alq3. However, it was never understood why and how the temperature treatments could have played such an important role, until recently we have discovered that such molecules tend to aggregate themselves in morphological states different from the well known crystalline phases. Annealing processes produce a phase transition among the previous aggregations, which improves the emission efficiency and the lifetime of Alq3 thin films. Moreover, these aggregations are fully described by a four components model, FCM, which has been validated by degradation experiments lasting 50,000 h, almost 6 yr, a world record in its own.
Moreover, it has been found that above 30,000 h the photoluminescence of thin films in the atmosphere decays faster than an exponential behavior, so that a zero order term has been added to the well known first order one in the decay equation. Preliminary simulations of experimental data have shown that the environmental conditions play a non secondary role in this zero order approach.
In addition, although the previous studies refer uniquely to the luminescent molecule Alq3, recent results by other authors seem to indicate that a general trend exists in organic luminescent compounds due to their molecular coordination, a matter of some importance for the properties of the emitting material in particular and OLEDs in general.
born in Narni,
, December 15, 1941 Terni, Italy
married with three children
Degree in Physics from the
Fellow, Italian Physical Society
Fellow, European Physical Society
Fellow, Coblentz Society
Fellow, Electrochemical Society
Award “Sergio Panizza” for outstanding contributions in Physics, SIF, 1993
Fellowship Consiglio Nazionale delle Ricerche, CNR, 1966
Fellowship CNR and Berkeley Physics Department, 1971, 1972
1965-1975 Assistant, Physics Department,
1967-1994 Scientist ENEA (former CNEN),
1972 Assistant Research, Physics Department,
1976-1977 Research Associate, Physics Department,
1984-1986 Adjunct Professor, Chemistry Department,
1987 Visiting Prof., Physics Department, Pontifical Catholic University of Rio de Janeiro.
1989 Visiting Professor,
1994-2008 Scientist, Head of Laser and Accelerators Division, ENEA,
Research spanned in times from EPR and NMR to cryogenics, color centers in alkali halides, optoelectronics, laser materials, and high resolution molecular spectroscopy. More recently, interests focused also on luminescent phenomena in insulating crystals and organic materials. Particular emphasis has been devoted to radiative and nonradiative processes which play a fundamental role in the optical absorption-emission cycle of matter. In the previous research fields, 270 papers have been published in refereed journals, 100 papers in technical reports, and 300 communications, of which 50 invited have been presented at scientific meetings. About 100 seminars have been delivered, 1 international conference chaired and other ones co-organized, among them 20 schools on spectroscopy at the International Ettore
RECENT SELECTED PUBLICATIONS:
(1) G. Baldacchini,
(2) G. Baldacchini, A.T. Davidson, V.S. Kalinov, A.G. Kozakiewicz, R.M. Montereali, E. Nichelatti, and A.P. Voitovich,Thermoluminescence of Pure LiF Crystals and Color Centers,J. Lumin. 122-123 (2007) 371-373.
(3) G. Baldacchini,
(4) G. Baldacchini, P. Di Lazzaro,
(5) G. Baldacchini, T. Baldacchini, P. Chiacchiaretta, R.B. Pode, and Q.-
(6) G. Baldacchini, P. Chiacchiaretta, R. Reisfeld, and E. Zigansky,The origin of luminescence blue shift in Alq3 composites,J. Lumin. 129 (2009) 1849-1852.
(7) P. Di Lazzaro,
(9) N. Akiyama, T. Shirosaki, S. Muramatsu, and G. Baldacchini, Vibronic Relaxation Processes of the FA Center in RbCl:Li, J. Lumin. 132 (2012) 1649-1655.
(10) G. Baldacchini, P. Chiacchiaretta, R.B. Pode, M.A. Vincenti, and Q.-M. Wang,Phase Transitions in Thermally Annealed Films of Alq3, Low Temperature Physics/Fizika Nizkikh Temperatur, 2012, v. 38, N. 8, pp. 985-992.
(11) G. Baldacchini and F. Baldacchini, Image Formation of the Turin Shroud: Hypothesis Based on Water Vapor Effects of Light Absorption, Sci. Res. Essays 7(29)pp. 2591-2602, 30 July, 2012.
SELECTED PUBLICATIONS EVER:
1. G. Baldacchini and V. Montelatici, A Contribution to the Study of Dynamic Polarization by Solid Effect, Nuovo Cimento, 68B, 253 (1970).
3. P. Cardoni and G. Baldacchini, A New and Simple Coupling Device for Transfer Tubes, Cryogenics 15, 151 (1975).
4. G. Baldacchini, U.M. Grassano, and A. Tanga, Electron-Spin Memory and Magnetic Circular Dichroic Effects in the Luminescence of F Center in KI, KBr and KCl, Phys. Rev. B20, 4357 (1979).
5. G. Baldacchini, D.S. Pan, and
6. G. Baldacchini, S. Marchetti, V. Montelatici, G. Buffa, and O. Tarrini, Experimental and Theoretical Investigation of Self-Broadening and Self-Shifting of Ammonia Transition Lines in the n2 Band, J. Chem. Phys. 76, 5271 (1982).
7. G. Baldacchini and U.M. Grassano, Mesurement of the Electron-Spin Polarization in the Relaxed Excited State of the F Center, Phys. Rev. B28, 4855 (1983).
8. G. Baldacchini, E. Giovenale,
9. G. Baldacchini, S. Botti, U.M. Grassano, L. Gomes, and
10. R.M. Montereali, G. Baldacchini, and L.C. Scavarda Do Carmo, LiF Films: Absorption and Luminescence of Colour Centres, Thin Solid Films, 205,106 (1991).
11. G. Baldacchini, G. Buffa, F. D’Amato, F. Pelagalli, and O. Tarrini: Variations in the Sign of the Pressure-Induced Lineshifts in the n2 Band of Ammonia with Temperature, J. Quant. Spectrosc. Radiat. Transfer, 55, 741 (1996).
12. G. Baldacchini, M. Cremona. G. d’Auria, R.M. Montereali, and V. Kalinov: Radiative and Nonradiative Processes in the Optical Cycle of the F3+ Center in LiF, Phys. Rev. B54, 17508 (1996).
13. G. Baldacchini, Colored LiF: an Optical Material for all Seasons, J. Lumin.100, 333-343 (2002).
14. G. Baldacchini,
15. G. Baldacchini,
16. G. Baldacchini, A.T. Davidson, V.S. Kalinov, A.G. Kozakiewicz, T. Marolo,
17. G. Baldacchini,
18. G. Baldacchini,
19. G. Baldacchini, et al. Soft x-ray submicron imaging detector based on point defects in LiF, Rev. Sci. Instrum. 76, 113104-12 (2005). This work has been selected for the December 1, 2005 issue of Virtual Journal of Biological Physics Research.