During the past decade, enormous progress has been made in growing ultrathin organic films and multilayer structures with a wide range of exciting optoelectronic properties. This progress has been made possible by several important advances in our understanding of organic films and their modes of growth. Perhaps the single most important advance has been the use of ultrahigh vacuum (UHV) as a means to achieve, for the first time, monolayer control over the growth of organic thin films with extremely high chemical purity and structural precision.1-3 Such monolayer control has been possible for many years using well-known techniques such as Langmuir-Blodgett film deposition,4 and more recently, self-assembled monolayers from solution have also been achieved.5 However, ultrahighvacuum growth, sometimes referred to as organic molecular beam deposition (OMBD) or organic molecular beam epitaxy (OMBE), has the advantage of providing both layer thickness control and an atomically clean environment and substrate. When combined with the ability to perform in situ highresolution structural diagnostics of the films as they are being deposited, techniques such as OMBD have provided an entirely new prospect for understanding many of the fundamental structural and optoelectronic properties of ultrathin organic film systems. Since such systems are both of intrinsic as well as practical interest, substantial effort worldwide has been invested in attempting to grow and investigate the properties of such thin-film systems. This paper is a review of recent progress made in organic thin films grown in ultrahigh vacuum or using other vapor-phase deposition methods. We will describe the most important work which has been published in this field since the emergence of OMBD in the mid-1980s. Both the nature of thin-film growth and structural ordering will be discussed, as well as some of the more interesting consequences to the physical properties of such organic thin-film systems will be considered both from a theoretical as well as an experimental viewpoint. Indeed, it will 1793 Chem. Rev. 1997, 97, 1793−1896

Ultrathin Organic Films Grown by Organic Molecular Beam Deposition and Related Techniques.

A field-effect transistor has been fabricated from polymer materials by printing techniques. The device characteristics, which show high current output, are insensitive to mechanical treatments such as bending or twisting. This all-organic flexible device, realized with mild techniques, opens the way for large-area, low-cost plastic electronics.

https://science.sciencemag.org/content/sci/265/5179/1684.full.pdf

All-polymer field-effect transistor realized by printing techniques

The organic thin-film transistor (OTFT) is now a mature device that has developed tremendously during the last twenty years. The aim of this paper is to update previous reviews on that matter that have been published in the past. The operating mode of OTFTs is analyzed in view of recent model development. This mainly concerns the distribution of charges in the conducting channel and problems connected with contact resistance. We also delineate what differentiates n- and p-type semiconductors, and show how this concept differs from what it covers in conventional semiconductors. In the chapter devoted to fabrication techniques, emphasis is placed on solution-based techniques and particularly printing processes. Similarly, soluble materials are given a prominent place in the section dedicated to the performance of devices. Finally, special attention is given to devices at the nanoscale level, which demonstrate a new route toward molecular electronics.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0884291400094504

Organic thin film transistors: From theory to real devices

Organic-inorganic hybrid materials enable the integration of useful organic and inorganic characteristics within a single molecular-scale composite. Unique electronic and optical properties have been observed, and many others can be envisioned for this promising class of materials. In this paper, we review the crystal structures and physical properties of one family of crystalline, self-assembling, organic-inorganic hybrids based on the layered perovskite framework. In addition to exhibiting a number of potentially useful properties, the hybrids can be deposited as thin films using simple and inexpensive techniques, such as spin coating or single- source thermal ablation. The relatively new field of "organic-inorganic electronics" offers a variety of exciting technological opportunities. Several recent demonstrations of electronic and optical devices based on organic-inorganic perovskites are presented as examples.

Organic-inorganic electronics

Field-effect transistors made from solution-processed organic semiconductors

The influence of deposition temperature on structure, orientation, and morphology of vacuum-evaporated sexithiophene films has been studied by using X-ray diffraction, UVvisible spectroscopy and scanning electron microscopy. We correlate this with the mobility of these films as measured in field-effect transistors. The X-ray study based on meridional 001 reflections shows evidence for various crystalline phases depending on the substrate temperature during vapor deposition. A high degree of orientation can be achieved even in several-micrometer-thick films deposited above 190 "C. It is shown that the field-effect mobility is substantially enhanced for deposition temperatures close to the melting point (290 "C), which is associated with a suitable orientation (002 being the single contact plane) and eventually a favorable crystalline structure and coalescent lamellae morphology.

O. Lagorsse

Papers

Polymorphism and Charge Transport in Vacuum-Evaporated Sexithiophene Films